Carsten Burkhardt's Web Project Paeonia - The Peony Library
PEONIES
The Manual of the American Peony Society
EDITED BY JAMES BOYD
Copyright 1928 by American Peony Society
PEONY-BREEDING
By A. P. saunders
SECTION I. PRACTICAL Structure of the Peony Flower.
THE peony flower consists of the following parts, proceeding from without inward: the calyx, the corolla, the stamens, and the carpels. The calyx is made up of sepals, and the co-rollaof petals, but with neither of these has the plant-breeder much to do, as they are non-reproductive parts, serving only, in the case of the sepals, to protect the inner structures while in the bud stage, and in the case of the petals, to make the flower conspicuous so that insects may find it. It may be remarked in passing that the sepals in some species of peonies possess nectar-secreting glands. This nectar has been called "extra-nuptial" because, in seeking it, insects do not effect the pollination of the flower. This sweet honey-like juice is much relished by both ants and bees, and, I may add, much disliked by anyone who has the task of disbudding peony plants in spring. One of the questions which the peony fancier has most often to answer is this: "Do the ants harm the peony buds?" It has been thought that they may carry on their feet the spores of fungi which adhere to the viscid juice on the bud, causing the development of the fungous disease which sometimes affects peony buds. But if the plant is in good health, it does not seem likely that this is a serious source of danger under normal weather conditions.
The stamens are numerous, conspicuous, and have a very telling color effect when the broad, glistening white or pink petals are brilliantly set off by their boss of gold in the center. A stamen consists of a slender, thread-like stem called the filament and a yellow sac at the end called the anther. This sac bursts open when the pollen is ripe—dehiscence, the botanist calls it—exposing the pollen grains, which in this type of flower are produced in enormous quantity.
The process of doubling is brought about by the transformation of the stamens, and sometimes of the carpels as well, into petals. When the change in the stamens does not go too far, a kind of strap-shaped petal is produced which still preserves remnants of the yellow anther along its edges. This sort of petal is characteristic of what are called the Japanese Type of
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peonies. In such flowers the narrow central petals are often twisted and striped, and pollen may be had from their swelled yellow edges by slitting them open with a sharp knife. I have made microscopic tests on a good many pollens obtained in this way from flowers of the Japanese type or from petaloid anthers from ordinary doubles, and have found them to be viable in most cases. I have also used such pollen for actual crossing, and the character of the seedlings so produced shows that the pollen is quite as good in actual use as it is under the artificial test. Remnants of anthers are often found on even very fully doubled peonies. On such a variety as Le Cygne some of the petals may be found here and there to show a thickened yellow edge containing pollen. This is important for the hybridist, since it gives him a source of pollen from flowers in which the process of doubling has been carried very far.
It was claimed many years ago by Marshall P. Wilder, an experienced grower of camellias and the originator of some fine varieties, that it was important in securing good doubles by cross-pollination to use pollen from partially transformed anthers rather than from normal ones. But much more complete and detailed evidence would be required to induce the botanist to believe that better results could be obtained in one case than in the other, provided the pollen were taken in both cases from the same flower. A. H. Fewkes reported, some years ago, that he had begun an experiment on this question with peonies, and that his results, so far as they went, tended to confirm Mr. Wilder's conclusions. However, the number of plants in Mr. Fewkes' test was too small to lead to any convincing result. (See Peony Soc. Bull., No. 2, p. 6.)
The carpels consist of three parts: a lower portion, the ovary, containing the ovules which will later become the seeds; then a short process called the style; and, at the end of this, the stigma. It is upon the stigma that the pollen is received in the pollination of the flower. The stigma in the young bud is dry, but at about the time the flower expands it becomes covered with a viscous fluid, and it is only when the stigma is in this condition that fertilization can take place. The pollen grain, which reaches the stigma at the proper time, sends out a slender thread-like growth called the pollen-tube, which penetrates through the style to the ovary; there it seeks out an ovule, enters it through a tiny opening in its wall, continues growing until it
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reaches the egg; then it bursts open at the tip and a little cell, called the sperm-cell, which was within the tube unites with the egg-cell. This uniting of a sperm-cell and an egg-cell is called fertilization, and from it the seed develops. Since only one pollen grain is necessary for the fertilization of each ovule, it is evident that in a seed-pod containing many seeds no two may have been fertilized by pollen from the same source. This would account in part for the extreme variations often observed among peony seedlings from the same plant, and even from one flower. No experiments are on record in which protected blooms of the peony have been fertilized by their own pollen and a set of plants raised from the seeds so produced. Such experiments would be of interest.
The processes of seed-production described above take place readily for plants having single flowers. But with the development of double flowers there comes a loss in the ability of the stamens and carpels to function in seed-setting, and so various grades of barrenness—even to complete sterility—are encountered. Such varieties as Le Cygne, Grandiflora, Mont Blanc, and Kelway's Glorious are usually without either carpels or stamens and are, of course, seedless. In some cases, however, carpels may be found occasionally on the lateral blooms, where the filling out of the flower has not gone so far as it usually does on the terminal blooms. I have had side blooms with large carpels on both Therese and Kelway's Glorious, though never on Le Cygne.
The stigma of the peony is often somewhat red in color, and in the process of transformation into a petal the red color becomes spread over a larger area and gives rise to those crimson stains which are so conspicuous on many double white or pink peonies.
Natural Pollination.
Peonies, if left to themselves, may be pollinated by three agencies:
(i) The flower may be self-pollinated, and this may lead to self-fertilization. No devices exist in the peony for the prevention of self-pollination such as are found in many other flowers. On the contrary, the anthers are usually curved over the stigma in such a way that as soon as pollen is shed it is inevitably deposited on the stigma, This may take place quite
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early in the history of the flower, as those who have hand-pollinated the peony well know, for the flowers often pollinate themselves even before the buds expand.
(2) After the opening of the flowers, visiting insects may bring pollen from other flowers of the same plant or from other plants; or, in clambering about among the stamens, they may easily transfer to the stigma some of the pollen of the same flower.
(3) Wind-borne pollen is apparently active in the fertilization of peonies. I am not aware that any direct observations have been made on the scattering of peony pollen by wind, but some varieties which are without stamens are strong and regular seed-setters, and yet insects are rarely seen in many of them. Primevere is such a variety, but there are others. It would seem, therefore, that in the height of the season there must be a good deal of pollen carried by the wind from one part to another of a group of peony plants.
The peony flower is apparently without nectaries except the external ones on the sepals in the bud stage. My own experience leads me to believe that the insects which visit peony flowers come mostly for the sake of the pollen. Insect visitors are much less common on double peonies than on singles. Butterflies are certainly unusual visitors to peony blooms of any type, and the bees which come so freely and so constantly to single peonies spend their time in tumbling about among the anthers with the busy-ness that is proverbial to them. We are much in need of some accurate observations on the insect visitors to peony blooms and on their activities during their visits.
Uncontrolled Pollination.
If the peony-breeder is working for practical results only, he may cross-pollinate the various plants of his choice by simply carrying an opened anther from one variety to an expanded bloom on another plant and transferring some pollen from the anther to the stigma of the selected flower. This method has the advantage of being quick and easy, but, like most quick and easy methods, it gives results that are only half-way satisfactory. For the flower to which the pollen is so applied may have been already pollinated by insects or by wind-borne pollen; and even if this has not happened, the anther selected for the cross may have been scrambled over by half a dozen bees that very morn-
Crown- and root-rot. The injured parts are infested Injury to peony
by fungus Rhi^octonia but this plant came from a field buds caused by
where root-knot was present and mulching with aphids—bud-in-
manure had been practised. Large plant was barren, festing insects.
plate XXV
Leaf-curl of peony. This plant grows this way each year, though formerly it was normal. The root system was very large and appeared normal. Many of the buds abort.
plate XXVI. Claire Dubois
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ing, each depositing on it some of the pollen of other flowers to which earlier visits have been paid.
Considering these things, it is plain that it would not be worth while to keep an elaborate record of such crosses, and, where this procedure has been followed, records have usually not been made. There is always a good chance, even by such a rough-and-ready method, that many of the seeds produced will be actual crosses between the two parents selected, and, if the cross has fine possibilities, some good results are likely to be produced.
If variation in the progeny is all that is desired, no cross-pollination is necessary at all. Since the peony has never been grown to develop strains that come true from seed, probably even self-pollinated blooms would give varied offspring. Under ordinary garden conditions most peony blooms are likely to receive pollen from several different sources, and so one finds seeds from a single white throwing a fair percentage of double whites and pinks, seeds from a double pink throwing single whites, and the like.
Controlled Artificial Pollination.
Where it is intended to keep accurate track of the results from definite crosses, certain precautions must be carefully observed. In the first place, care must be taken to keep the bloom which is being used as female from being fertilized by unknown pollen before or after it has been worked over. And, in spite of all precautions, accidents will occasionally happen. Anyone who has attempted the cross albiflora X lutea or albiflora X moutan, i.e., between the shrubby and the herbaceous sections, is likely to have been rewarded from time to time with a seed or a few seeds. These are sown in high hopes—I speak in recollection of ten years ago—and although the young seedlings on germination show a discouraging likeness to others which are "pure albiflora" one grows them on year after year until they reach the blooming age, the springs of hope however running a little drier each year as the plants show more and more clearly that they are only the results of a mesalliance. And, sure enough, when blooming-time comes they stand revealed as albiflora pure and simple, fit only for the rubbish-heap. I would not like to say how many alleged crosses of lutea and of moutan on albiflora I have thus trustingly reared to maturity only to see my hopes
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betrayed in the end; but even a few such are enough to convince the worker that no trouble is too great that would guarantee him against such wasted efforts.
It has already been said that the anthers in single peonies often dehisce before the bud expands. Hence, in cross-pollinating, it will not do to take expanded blooms, at least in the case of single flowers. In order to protect these from self-pollination, the stamens must be removed while the flower is still in the bud stage. The stigma at this time is not likely to be ready to receive pollen, and in that case the flower must be bagged to protect it from wind-borne pollen, and pollinated on a later day. I use specially colored bags for the blooms that are thus waiting. In deciding at just what stage the buds should be stripped one has a choice of dangers. The nearer they are to opening, the more likelihood of the anthers having already burst; the farther from opening, the likelier that the tender and immature stigmas will be injured by exposure to the air. I think that it is of great importance that the stigmas should not be touched by any hard object—pincers, magnifying glass, or the hand—as such rough contacts cause them to blacken in spots, and must affect the success of the cross.
In crossing on double varieties, the expanded flowers may usually be used, for in these the stigmas are often protected by the innermost petals and do not become exposed, indeed do not mature, until after the flower has opened. This would not be true with varieties like Marie Crousse or Duchesse de Nemours (Calot), which almost immediately on opening spread and completely expose the carpels. It need hardly be said that, in preparing a bloom for crossing, the petals should be completely removed. If bagged with the rest of the flower after pollination, the petals may rot and spoil the cross.
If only a few crosses are being made, it may be sufficient to bring anthers from one flower to another as needed, but if the work is being carried out upon a larger scale, it is altogether better to gather a quantity of pollen at once and preserve it on a watch-crystal, which may be taken into the field and the pollen transfered to the stigmas with a tiny sable brush. This is the method I have always used. A small bottle of pure alcohol may be carried in the tool-basket, and if the brush is moistened from time to time with a little alcohol, the pollen grains that have to it from earlier crosses will be destroyed.
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When pollination has been effected, a cardboard tag or a wired wooden label, recording the parentage and date of the cross, is fastened to the stem. A paper bag is then tied over what remains of the flower, and nothing more need be done till the following September when, on shaking the stem, the seeds may be heard rattling about in the bag—if there are any! If one is working on a small scale, the bags may be removed when the stigma becomes dry; but in that case the seed-pods must be constantly watched as the time approaches when they will open and scatter their seeds.
Dr. Stout tells me that he uses the tip of the finger for transferring pollen to the stigma. With the deepest respect for his judgment and skill, I feel that a small brush is the safer instrument, at least in my hands. No pressure should be applied to the stigma, even when using quite a soft brush, but the pollen may be gently "dabbed" on without any risk of injuring the delicate papillae on the stigmas.
Gathering and Storing Pollen.
The hybridizer who gathers his stamens as he needs them is subject to the vicissitudes of the weather, and after a heavy rain he cannot tell whether the pollen he gathers will have any vitality. It is better to have pollen in storage if any considerable amount of work is being done. Peony pollen keeps very well, and it is an immense convenience to have a supply of good dry pollen at hand for use at all times.
My practice is to select a flower with anthers just beginning to open, pull off a few dozen of them with the fingers, if clean, or with a pair of forceps, and lay them on a watch-glass previously labeled. This means, in the case of single peonies, finding blooms that are just expanding, for if the bloom is fully open the pollen will be already too much scattered and may even be contaminated by visiting bees from other flowers. It is a mistake to choose a young bud, open it up, and tear off the unripe anthers; these are not likely to give good pollen even if kept until they burst of their own accord.
When half a dozen or a dozen pollens have been gathered— or as many as may be conveniently carried—they should be brought into the house and spread upon a table or shelf where they will be dry. Usually within a day or two they can be shaken out by tapping the watch-glass on the table or on the finger-
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knuckle, and if the pollen is strong it will come out of the anthers in great abundance. Small Petri dishes may be used instead of watch-glasses, and they have the advantage of being supplied with covers.
After shaking out a sufficient supply, the anthers may be thrown away and the pollen put into dry storage. For storing pollen I use what is known to the chemist as a desiccator. It is the same kind of vessel as a humidor for tobacco. In the bottom of the vessel is placed some substance which will keep the atmosphere almost dry. I use a mixture of concentrated sulphuric acid and water in the proportion by volume 30 of acid to 45 of water. As this acid is very corrosive, it would probably be better for those not accustomed to handling chemicals to use fused (granulated) calcium chloride which can be procured through any druggist and will answer about as well. (See article on the Preservation of Pollen, Am. Peony Soc. Bull. No. 6, pp. 2-9.)
Where a number of pollens are to be preserved, the following device may conveniently be used for stacking the watch-glasses. Fasten three small fragments of wood at intervals around the upper edge of each watch-glass. The glasses may then be stacked, with sufficient space for the pollen, and at the same time six to eight glasses may be accommodated within one inch of vertical space with enough stability so that they are not easily upset. Where pollens are to be preserved some such plan must be adopted, for, if they are left exposed to the air, though they may keep very well in dry weather they will be by no means so happy if the weather is rainy. With the desiccator method of preservation one may be quite sure that the samples will suffer only a very slow and gradual lessening of vitality. I have had pollens preserved in this way still show some little vitality nearly a year after they were gathered.
Another convenient method of keeping pollens in a desiccator is to use what are called shell vials in place of the watch-glasses. These are a kind of homeopathic vial and may be stood on end in the desiccator and so stored with a great economy of space. For those who have no means of supplying themselves with such glassware as is mentioned above, a quite satisfactory desiccator may be made by using a quart preserving-jar with a wide mouth. Put in the bottom an inch or so of granulated calcium chloride, on top of this a layer of cotton batting, and
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let the small vials containing the pollens rest on this. The cover should have a rubber ring to prevent leakage of moisture from outside.
Another matter of great moment to the practical worker is the testing of pollens to determine their vitality. It is only too easy to be betrayed into spending many precious hours in the field making crosses with pollens that have no vitality at all and are incapable of yielding any results. Furthermore, when pollen is collected from early-blooming varieties and is used perhaps two months later, it is absolutely necessary that the breeder should know whether it is still viable.
All the pollens of Chinese peonies that I have tested or used in crossing show a high vitality, and I have no doubt that most if not all of the Chinese peonies with stamens give viable pollen. But with hybrid forms it is a very different matter. We do not know much about the origin of the varieties of P. officinalis, P. peregrina, P. arietina, and the like, which are offered in catalogues. Where they are merely mutants from the original species or from other garden forms so derived, the pollen is likely to be sound and healthy. But if other blood has been introduced and the garden variety is a true species-hybrid, it may be sterile. It is true that the possession of good pollen usually accompanies the ability to set seed, and that a plant that sets no seed is likely to have sterile pollen; but this cannot be taken as an invariable rule. The Lemoine hybrids of P. Wittmanniana have never been known to set seed, and yet an examination of their pollens has shown that although those of Avant Garde and Mai fleuri are sterile, that of Le Printemps shows a considerable degree of vitality. Whether it can be successfully used in making a back-cross on P. sinensis is another question. A good many attempts have already been made without result, but the character of the pollen would indicate that the project is not hopeless as it would be with the other two varieties.
Some years ago I bought P. Wittmanniana from a foreign nursery and spent a good deal of time in making crosses with its pollen. When later on I came to make pollen-tests I found to my chagrin that the pollen was entirely sterile. The truth is that the plant was not the species at all, but a hybrid form near enough in general character to the species so that it could be sold as such. An exactly similar experience awaited me in
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the case of a plant of P. anomala from the same nursery. Its pollen also turned out to have no viability, although pollen of the same species from another source gave positive results.
I cite these cases merely to show how necessary such tests are to the working hybridist.- We know only too well how hard it is, even now, to be sure of the authenticity of some of the Chinese peonies. And it must be remembered that among other species the same conditions exist, more or less, which prevailed among the varieties of P. albiflora twenty-five years ago. No guarantee of the correctness of a name can assure the buyer that his plant is true; but a pollen-test will show at least whether or not its pollen is sterile!
Nevertheless, it is to be remembered that pollen-tests are made under artificial conditions, and one must be prepared to find occasionally that positive results may be had under the microscope but the pollen yield nothing in practical use. It has been found with some species of plants that pollens which do not form pollen-tubes in the ordinary solutions used in microscopic tests, may be induced to do so if a fragment of stigma is added to the solution. This would indicate that a pollen may give negative results in the laboratory test and yet be good in actual use. I think, however, that the reverse would be found to be much more common, namely that pollens which gave positive results in a test would fail when applied to actual fertilizations.
The Testing of Pollens.
The procedure in making such artificial tests is to prepare solutions of cane-sugar of different concentrations, all containing a small percentage of agar jelly; place drops of these on microscope slides, put a small quantity of the pollen to be tested in each drop, leave for six to twelve hours, and then examine under a low power of the microscope. If the pollen is strong the whole field will be an intertwined network of pollen-tubes, whereas the sterile pollens remain unchanged.
In the case of weak pollens it is often possible to forecast the result from the beginning, for they usually have a dry, shriveled look, in sharp contrast to the plump appearance of healthy pollen. Among the hundreds of pollens of species crosses among peonies which I have examined there has been no case where a bad-looking pollen has given abundant pollen-tube formation. The usual appearance of such poor-looking pollens is a field of
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small more or less shriveled grains with here and there some normal grains; and a few of these will almost invariably show pollen-tubes. The cases are very exceptional in which there is really complete sterility. But where the number of good grains is less than 10 to 20 per cent there is not much hope of success in any crosses in which they are used.
My practice is to make up a solution of agar jelly of i per cent concentration or a little less, then divide this into three portions and add to these 5,10, and 15 per cent of cane sugar respectively. Solutions of approximately these concentrations may be made up as follows: Place half a teaspoonful of powdered agar jelly (weighing about i gram) and a teaspoonful of table sugar (weighing about 4 grams) in 20 teaspoonfuls of water (weighing about 100 grams). Heat to gentle boiling until agar and sugar are dissolved. Make up two other solutions by the same formula except that in one of them two teaspoonfuls of sugar are used, and in the other four, the quantities of agar and water remaining the same.
If the solutions so obtained are to be preserved for any length of time, they may be divided among a number of test-tubes, each plugged with cotton batting, and then sterilized by boiling. To set up a row of slides, one tube of each concentration is heated, and one drop taken from it and placed on each microscope slide. Every slide will thus have three drops of different concentrations on it. The pollens are immediately placed in very small quantity on the three drops of half-gelatinized liquid, and the slides placed without delay in a desiccator provided with water in the bottom to keep the atmosphere moist and prevent the test drops from drying. This is a most vital point, for if the drops are allowed to evaporate they will soon be so much increased in concentration that pollen-tube formation will be prevented.
A simpler arrangement will be to lay the slide across the top of a small dish containing water, and then over the dish and slide place a glass cover, such as the cover of a cheese-dish.
Microscope cover-glasses must not be used on the drops, for the exclusion of air prevents the production of pollen-tubes.
Furthermore, for some unknown reason, the sugar solutions gradually deteriorate and must be made up fresh every week or two. If this is not done, negative results are likely to be obtained with even very good pollens.
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It will be evident that making pollen-tests involves both time and trouble; but it is an unavoidable necessity except where one can be sure without them that the pollens he uses have a high vitality. Perhaps some day we shall have a testing laboratory like the U. S. Bureau of Standards to which we can send our samples for test. But in the meantime we must attend to the matter ourselves; and, after all, the time spent in making pollen-tests is not much in comparison with the time that may easily be lost in attempting to make crosses with dead pollens.
There seems to be much more variation in the viability of pollens among standard varieties of iris than among peonies, and Dr. A. B. Stout, of the New York Botanical Garden, has carried out for the American Iris Society two quite elaborate series of tests to determine the viability of pollens in the irises. Among the Chinese peonies there is probably no need of such tests; and with the other species, much would depend on the source of the plant, these species and their varieties being as yet so little standardized.
Sowing Seeds.
The seed of herbaceous peonies may be planted in open frames and left until it germinates. Whether sown in drills or scattered it should be covered with about an inch or two of earth. If it has been gathered before it has become thoroughly dried, some of it may germinate in the following spring. The normal course with fully ripened seed is for it to remain quiescent until the following summer, when, in July or August, a root is thrust out which may go down six inches into the soil; but no leaf-growth is made until the following spring, when the first little red leaves push their way up through the ground and give a thrill to the patiently expectant breeder. On account of this long wait it is important that the seed should be provided with permanent labels when planted. These should not be of wood but of metal in one of the patterns now widely used.
In the case of precious seeds it is probably wise and with some species it is apparently necessary to protect the seed from severe freezing, especially during the second winter. This may be done by sowing in boxes which are stored for the winters in a frost-proof cellar.
Some of the early-blooming species, P. macrophylla, for instance, usually germinate the first spring after planting, even when the seed has been thoroughly dried before being put into
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the ground. But with these, also, the beds should be left until the second spring to give the laggards a chance. My practice is to leave the seedlings undisturbed in the seed-beds for a full year after germination and then, in July, to move them into the rows where they are to remain. If the plants are moved earlier than July the foliage will be too soft to withstand the drying of wind and sun, but by that time it will have hardened sufficiently. The advantage of this early transplanting is that the plants may take hold before autumn and are less likely to be thrown out by frost in winter.
The slow germination of peony seeds appears to be due to the very dense seed-coat which only slowly softens to admit moisture. Efforts have been made to shorten the process by softening the seed-coats through immersion in strong acids or alkalies, by filing, sand-papering, or even by removing the seed-coat altogether. No such treatments have come into general use, and there is need of more experimentation before a trustworthy method can be worked out to which one would be willing to subject very precious seeds. If there is any safe way of bringing on germination so that a year may be saved, it would be a great boon to peony-growers to have it generally known.
Mr. W. H. Thurlow told me this curious story of quick germination. A pod of seed of some special interest was broken off in cultivating down the row, perhaps about the first of August, certainly long before the seeds had begun to turn brown. He opened the pod and planted the yellow seeds, and within a very few weeks—less than a month—had a fair germination.
It has often been claimed that seed that is taken from the pods as soon as they begin to open, i.e., when the seed is brown but not yet thoroughly dried, will, if promptly sown, give a good stand of seedlings in the following spring. This would probably depend partly on the latitude, for in regions to the south the seed not only matures much earlier but has also a longer period of warm weather in the autumn before winter closes in.
Unless the soil in the field is warm and friable it will be a kindly act when digging out a bed of seedlings to save the weaklings and set them back into other frames for a year or two to accumulate more endurance to meet the difficulties of life in the open field.
A lath screen over a seed-bed is much to be desired. The
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young peony loves partial shade and protection from rough weather, and a little extra care of this sort will make the difference between life and death for many a little nestling that has made a weak start.
When the plants go into the field, the distance in the rows and the distance between the rows must be decided in relation to the available space, method of cultivation, probable destiny of the plants, and the like. I set my rows about 3 to 3^ feet apart, to allow for cultivation with a gasoline cultivator. The plants, if ordinary seedlings of Chinese peonies, may go about a foot apart in the rows, for after they come to blooming age they will (or should) be rapidly weeded out, and this will give sufficient space for the better ones which are to be reserved for longer observation. With true hybrids it is a different matter. They need watching over a much longer time, and indeed one should be slow to throw away true hybrid plants in a genus where the maturing process takes so many years; one is likely to regret it later, for there are questions of sterility, of leaf-character, or of root-character that will insist on cropping up later when other plants of the same or of other crosses have matured; and the hybrid that is once thrown out can never be restored to life nor can anything be produced again that will be identical with it.
Peony plants vary a good deal in the age at which they set their first bloom. In a batch of seedlings there will be a few, perhaps, that will bloom the second year after germination, but most of them will set their first blooms in the third or fourth year of their life above ground. Some will take a year or even several years more. I remember M. Denis, the famous iris breeder, telling me in his garden in the south of France that he had once raised a seedling peony, a cross between two white varieties, and that after he had kept it for more than twenty years and it had never bloomed he lost patience and threw it away. But one must learn not to be too impatient!
There is an impression in the minds of some that the plants that come latest to the blooming age are the most likely to show high quality. Whether this is based on any exact observations is open to question. It is certainly true that a large proportion of the single-flowered sorts in a group of seedlings will come into bloom at a younger age than the doubles. Seedlings of good color should be left for two or three years after they reach
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the blooming-age in order that they may fully develop their individual characteristics; if they have not established themselves as something new and desirable at the end of that time they should be pitilessly discarded.
I should like to add a word of gratitude to Dr. A. B. Stout, for his helpful suggestions regarding the material included in this section.
SECTION II. HISTORICAL
The remote history of the Chinese peony goes back into China where, in a general sense, it is traceable for more than a thousand years. Beginning as the wild species P. albiflora, it gradually spread throughout northern China where it was cultivated for medicinal use—even for food—and also for garden ornament; and the evidence leaves us in no doubt that it was grown on a very large scale. There is a record in 1596 of at least thirty improved varieties then in existence, while a document that goes back to the eleventh century states that the herbaceous peony was at that time very widely grown in China, and that it existed in white, pink, and red varieties. We do not think of the peony as a medicinal plant, but our forefathers had a faith more like that of the Chinese in the curative value of plants, and in Hill's British Herbal of 1756 we find it claimed for the peony (P. officinalis, no doubt) that "it will alone cure that disagreeable disorder, the night-mare."
Evidently, then, the herbaceous peony enjoyed a wide esteem in China. The tree peony has a parallel and similar, but always a more glorious, story.
So far as we can learn, the Japanese derived their herbaceous and tree peonies from China, and it is doubtful whether they effected any very great improvement in either of them.
At the beginning of the nineteenth century the first herbaceous peonies were imported from China into England. These were given the names: Fragrans, Whitleyi, Humei, Pottsi, and the like. The beauty of these flowers made a deep impression on English and continental horticulturists and almost at once there began an active development of new and improved kinds, which has continued with ever-increasing enthusiasm up to the present day. During the century that has elapsed, the number of named varieties introduced into commerce has been almost beyond belief. It is probably no exaggeration to say
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that two to three thousand distinct forms have been named and sold, or offered for sale, within that period.
This is the race which we call Chinese peonies, or sometimes Pteonia sinensis, or, more correctly, P. albiflora. In beauty and variety of color, in size, and in perfection of form the European sorts far surpass the original introductions.
It is an interesting question whether any other blood than that of P. albiflora has gone into the making of these wonderful flowers; and the statement has often been made by very competent authorities that many of our "Chinese" peonies of today are the results of crosses between the original varieties brought over from China and some of the European species such as P. officinalis, P. peregrina, and others, which already existed in a number of distinct forms in English and continental gardens.
In one case, at least, the record of an individual grower seems to support this view, for it is reported of Lemon that in 1824 he raised a number of seedlings of P. officinalis, from which came P. anemoneflora alba and P. grandiflora nivea plena. Now this P. grandiflora nivea plena is extant in our gardens today and it is fully typical of the race of Chinese peonies. So that, if it could be established that it was a seedling of P. officinalis, it would be reasonable to suppose that many others of the great race might have a similar ancestry. The statement regarding Lemon's seedlings, however, occurs in a paper by George Paul in the Journal of the Royal Horticultural Society for 1890, and in its original form it reads "his (Lemon's) kinds were mostly obtained from P. officinalis, syn. sinensis, and amongst his earliest varieties were grandiflora nivea, etc." Thus, if Paul, and perhaps Lemon, did not distinguish between sinensis (i. e. albiflora} and officinalis, this piece of evidence falls completely to the ground. The fact is that in the earlier years of peony culture the specific names were not used with as much discrimination as they now are, and just as Paul here drops into the error of confusing officinalis and sinensis, so Thunberg, a little earlier, used the name officinalis even for the Chinese tree peony, P. moutan. Hence, the mere fact that records exist of crossings between officinalis and sinensis is no real proof that such crossings were made.
If we turn to consider internal evidence we fail to find much support for the view that officinalis blood has gone into the production of our Chinese peonies. A characteristic of
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P. albiflora type, as of the whole race of peonies derived from it, is that it bears several flowers to a stem, whereas P. officinalis bears only one. The root system of P. officinalis consists of a group of fusiform tubers attached to the crown by thin strings. In the Chinese peonies, on the contrary, the roots thicken toward the crown, the whole root system is rigid, and one never sees anything to suggest intermediate forms. The foliage of the Chinese peonies, further, shows no likeness whatever to that of the officinalis varieties but does have the general character of the wild P. albiflora.
Moreover, during the past ten years I have raised a considerable number of hybrids—about fifty—between the Chinese peonies and various forms of officinalis; and while this strain shows, on one hand, a distinct departure in general type from the officinalis parents, it differs still more distinctly from its albiflora ancestry. The leaf character is nearer officinalis; the root system is intermediate between the two but has preserved the character of officinalis in its ability to form buds on root fragments, a power almost completely lacking in the Chinese peonies. Further, these plants have so far been sterile, i.e. they have set no seed, and in most cases yield completely sterile pollen. In short, no one comparing this group of plants with a group of the ordinary albiflora varieties could believe that they were of similar parentage.
And as far as authorities are concerned, they are not lacking in support of the contention that our Chinese peonies are pure derivations from P. albiflora. Vilmorin, in his "Fleurs de Pleine Terre," says, in speaking of the type albiflora, "from which have probably come (by sowing seed and by intelligent culture) the numerous varieties of peonies known under the name Chinese peonies;" and in a letter to me on this subject, M. Henri Correvon expresses himself as follows: "I cannot admit that the garden peonies we call Chinese or albiflora are the result of a cross. . . . They are certainly variations of the type albiflora and not crossed with others."
Furthermore, Prof. C. S. Sargent, writing in Garden and Forest in 1893, says: "Nearly all the late-flowered peonies in cultivation are forms of the Siberian P. albiflora."
I do not think I can do better at this point than to quote the introductory paragraphs from the famous catalogue of peonies published by Krelage in 1892. The document is rare. It gives
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Krelage's own views on the origin of the Chinese peonies, and since it gives also, in concise form, a history of the early period of peony cultivation in Europe it may appropriately find a place here:
Among the herbaceous peonies cultivated in our gardens no one species has played such an important part in the vast improvement that has taken place within the last years as the Chinese peony, P. albiflora, of which there are no less than 500 distinct double-flowering varieties described in the present catalogue.
The typical species is a native of Siberia and China, from whence it was introduced about 1780, and is very distinct from all other species of the genus.
Nearly a century ago George Anderson devoted a deal of attention to this genus, and being a keen cultivator as well as a good botanist, he dealt with peonies both from a cultivator's and a botanist's point of view. The result of this study of the genus he published in the Transactions of the Linnean Society (Vol. XII, 1817), where the following varieties of P. albiflora have been described, viz.:
(1) uniflora, Anderson (Bot. Mag. tab. 1756).
(2) vestalis, Anderson (Andr. Bot. Rep. tab. 64).
(3) sibirica, Anderson.
(4) Candida, Anderson.
(5) Whitleyi, Anderson (Bot. Reg. tab. 630; Andr. Bot. Rep. tab. 612).
(6) fragrans, Anderson (Bot. Reg. tab. 485).
(7) Humei, Anderson (syn., edulis, Bot. Mag. tab. 1768).
(8) rubescens, Anderson.
(9) tatarica, Anderson (Bot. Reg. tab. 42, Parad. Londin. tab. 78). From these varieties those marked (5), (6), and (7) are double flowering, the others being single or semi-double.
Shortly after the publication of this monograph some few varieties, obtained from seed, nave been described by the Prince of Salm-Dyck, who was a great lover of these plants and possessed a very celebrated collection of them; these varieties were grandiflora, Salm-Dyck, and spectabilis, Salm-Dyck.
About 1822 two semi-double forms were introduced from China, viz.: Pottsii, Sabine (Bot. Reg. t. 1436) and Reevesii, Sabine.
About the same time a French horticulturist, Mr. Lémon began to obtain garden forms from seed. His first acquisitions were belliformis, grandiflora carnea, grandiflora nivea, edulis superba, etc.
A few years later his countryman Mr. Modeste Guérin had great success in hybridizing several forms of the Chinese peony and soon possessed one of the most beautiful collections of this noble plant.
Meanwhile a Belgian amateur, Mr. Buyck, obtained also very good seedlings, such as lilacina superba, plenissima rosea superba, tricolor flavescens, triumphant, etc.
In those days herbaceous peonies were plants of great value. In the part for January, 1839, of the Revue Horticole we read that the variety festiva was offered by the firm of Makoy, who had got the stock of it, at the price of 250 shillings each. From the same periodical
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(June, 1842) we learn that the new seedlings of that year were priced as follows:
Comte de Paris each 80 s.
chrysanthemiflora each 80 s.
Reine des Francais each 65 s.
Reine Hortense each 40 s.
Although nowadays these very old varieties may be had at very low prices, it may be stated as a proof of their great horticultural merit that almost all these sorts are in cultivation still, although many hundred new varieties have been raised since that time.
For several of these later varieties we are indebted to the late Mr. Parmentier, Mayor of Enghien, in Belgium, whose splendid collection was sold in 1853, and also to the French nurserymen Mr. Victor Verdier and Mr. Calot, who inherited a large collection from an amateur, the Count of Cussy, and continued the collecting and production of seedlings until 1872. [Correction of Dr.Burkhardt 2005: The Collection of Count of Cussy was a present of Imperatresse Josephine before her death, the wife of Napoleon. She had the plants from the Emperor of China and cultivated them in Malmaison – quoted from Michel Rivière's book „Prachtvolle Päonien“, Ulmer 1996]
Other successful raisers were Delache, Van Houtte, Gombault, Pel, Delecourt-Verhille, Donkelaer, Foulard, Miellez, Salter, and lately Crousse, Méchin, Dessert, and Kelway.
So by careful selection of varieties our collections have been brought up to the high standard which the varieties composing them have now attained, the seedlings of Calot and Crousse dominating all others, such as Madame Calot, Jules Calot, Souvenir de Gaspard Calot, Madame Crousse, Modèle de Perfection, etc.
In England herbaceous peonies have been garden favorites since 1885. Rather old varieties, such as Festiva maxima (1851), Constant Dewey (1868), Daubenton (1880), Madame Emile Galle (1880), and Claude Lorrain (1884) have been awarded First Class Certificates of the R. H. S., R. B. S., and other societies in 1886, 1890, and 1891—a new proof of the excellence of these old continental varieties.
Since the foundation of their establishment, E. H. Krelage & Son have made a speciality of the cultivation of all kinds of peonies, the very first medal they obtained (1833) being a first prize for a well-grown plant of Peeonia moutan shown in full flower in February. In later years their collection of tree peonies received many high awards.
It will be noticed that Krelage in his mention of the earlier raisers of peonies makes no suggestion that they used other species for intercrossing with the Chinese forms. He does say, as is no doubt true, that they made crosses between the different forms of the Chinese peony which were available to them. These forms, at that time, were often given specific rank as Pottsi, Reevesi, Humei, edulis, etc. No doubt then, as in later years, many fine seedlings were raised by simply gathering and sowing seed of the best available sorts, without any hand-pollination at all. The term "hybridist," as popularly used today, indicates nothing more than a raiser of new varieties, quite irrespective of whether or not he does any hand pollina-
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tion, and many of us would certainly call the offspring of a fertilization of Primevere by Lady Alexandra Duff "hybrids." It is as well, therefore, to remind ourselves occasionally that the only true hybrids in the scientific sense are those in which botanical species are intercrossed. But since the limits of botanical species are notoriously hard to define, and in the genus Paeonia more than in most, we are left in the vague after all.
The three greatest raisers of peonies in France in recent times, are unquestionably Crousse, Lemoine, and Dessert.
With regard to Crousse's methods there is an interesting letter from Crousse himself, quoted by Mrs. Edward Harding in her excellent book, "Peonies for the Little Garden."
I started my first seedlings about 1869. I did not then have the time to employ artificial fertilization, therefore I proceeded differently. I omitted from my collection all flowers of inferior quality, leaving only the strictest selection of the most beautiful varieties. I harvested, and sowed, as soon as they ripened, all the seeds which were produced. It was always thus that I proceeded when I wished to secure seedlings. ... I grew as many seedlings as possible, according to the space at my disposal.
M. Dessert made to me substantially the same statement regarding his methods of work when in 1923 I visited that historic garden of his at Chenonceaux where so many beautiful new things first saw the light. I asked him whether he had used hand-pollination in the production of his seedlings, and he answered, "A little, sometimes, mats, sans precautions." By which I have no doubt he meant that he occasionally aided the bees and the wind by carrying about some stamens from varieties he liked, and touching a stigma here and there with the pollen. And for the practical and always busy nurseryman this method of procedure is probably as likely as any other to result in fine seedlings—provided always that the plot is kept free from undesirable pollen-bearing types. I cannot see, however, that there is any special virtue, as some growers seem to feel, in not pollinating by hand. One hears them say reproachfully "No, I leave all that to the bees." The argument seems to be that in leaving it to the bees one is in some way fulfilling the plans of God better than by using one's own intelligence.
Concerning the methods used by Lemoine, I may quote from a letter recently received from him. "I have never sown seeds of herbaceous peonies which I had not fertilized by hand. It is true also that I have never kept records of their parentage."
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Certainly it would be of great value to breeders of the present and of the future if they could know from what crossings sprang such varieties as Therese and Solange; but not less interesting if we could go back and find out of what parents sprang Walter Faxon and Lady Alexandra Duff. Would that peony-growers might take this lesson to heart, and in enriching our gardens with new and beautiful forms, leave such a record of their methods that those who are to come after may be able to work more intelligently toward the production of still lovelier things!
Lemoine's work has been by no means confined to the species P. albiflora. He has given us two new and beautiful strains of true hybrid peonies; one of these was produced by crossing P. Wittmanniana with the Chinese peonies; these hybrids bear the names Le Printemps, Mai fleuri, Avant Garde, and Mes-sagere. They have never been appreciated at their true worth, for though sadly fugitive they are of such beauty that no garden can afford to be without them. The other strain resulted from crosses between the two shrubby forms lutea and moutan and includes those startling apparitions in yellow, amber, and red which bear the names L'Esperance, La Lorraine, Surprise, etc.
The firm of Kelway & Son, in England, in spite of their notorious carelessness in the matter of names, must always be given credit for having originated some of the finest peonies that have come from any source. Lady Alexandra Duff, Baroness Schroeder, James Kelway, Kelway's Glorious—these are enough to atone for a multitude of errors.
As to their system of work we have little information. Mr. George Paul, in the paper to which reference has already been made, quotes a letter from William Kelway dated 1890, and Mr. C. S. Harrison, in his "Manual of the Peony" (first edition, P- 5)j gives a letter from the same source dated 1901. Neither of these letters yields any exact information as to how the Kelway seedlings were produced, though Mr. Kelway speaks in his letter to Mr. Harrison of the "thousands of hours of my life during the past thirty years" which have been occupied in cross-fertilizing, and he lets it be inferred that he was dealing with a number of distinct species. The evidence does not tend to show that there were any true species crosses made at the Kelway establishment; it is much more likely that crosses were made between different forms of the Chinese peony, of which many fine kinds were already available.
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In the letter to Mr. Paul, Kelway tells of finding a collection of peonies in an old-fashioned garden in 1863, and these plants, apparently, formed the material upon which he began his work. On referring to the Kelway catalogue of 1899,1 find an imposing list of new single and double peonies bearing the name of Kelway, and also in a separate section a group of "May-flowering peonies" including type species, corallina, decora, officinalis, etc., and some derived forms. All the names in this group, however, may be found in other lists of the time, and indeed many more appear in the catalogue of Barr & Sons of the same year. Nor do I find in any of the later Kelway lists anything outside of the albiflora group that is claimed as a Kelway origination. I think it may then be taken for granted that Kelway produced no new forms by the intercrossing of species and that the collection he had from the old-fashioned garden of his discovery in 1863 were at least in the main, Chinese peonies. If so, what are we to say to his conjecture based on the fact that some Roman pavements had been uncovered in the same parish, that "the peonies may have been brought there by the .Romans"?
Messrs. Barr & Sons are to be credited with a few good forms of Chinese peonies, but with none that has attained the highest rank in that class where competition has been so keen. Helena Leslie, Lottie Collins, and a few other names, are familiar in peony lists, but we know them scarcely more than by name. On the other hand, with the European species, officinalis, decora, arietina, etc., it appears that the firm of Barr & Sons must have done a good deal of work. Exact information is again wanting, but a study of the Barr catalogues between 1890 and 1900 reveals an increasing number of such varieties, many of them marked "new." Among these are the beautiful plants drawn from officinalis and from lobata, such as Sunbeam, Ceres, Charmer, Otto Froebel.
Most of the American growers have probably followed the usual course in raising their seedlings, i.e., gathering seed from their best varieties. If we could go backward in time and see John Richardson at work in his garden, we might learn something worth knowing, for this man, in a small plot, and possessing only a moderate collection of varieties, was able by some touch of genius to produce such beauties as have not been surpassed, if equaled, among all the tens of thousands of seedlings that have
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been grown in the many years since he lived and worked. Prof. Robert T. Jackson is the authority on John Richardson and has given us a detailed account of his garden and of his seedlings in the Transactions of the Massachusetts Horticultural Society for 1904. Of Richardson's method of work and of the extent of his material Prof. Jackson says in a recent letter: "I agree with you that it is an extraordinary thing and a mystery how Mr. Richardson managed to raise so many choice seedling peonies. He never did any cross-fertilization I am very sure. He was not at all a scientific man, simply a gardener to the backbone and loved raising seedlings of everything that came to hand. He had a relatively small bed of seedlings—'candidates for fame' he jocosely called them. This bed, as I recall it; was not larger than an ordinary room of twelve to eighteen feet square. He had no single peonies and therefore only occasionally got seed as is the custom with double peonies."
With regard to Hollis we have the testimony of Mr. Everett P. Wheeler, a friend of Hollis, in the following words quoted from a letter to me: "Of course, I could not say that all of his seedlings were raised from hand-fertilized flowers. But I do know that it was his practice. His brother and his wife, with whom he lived his last years, said that it was his custom, for he could be seen most any day during the season going about the field with brush in hand carrying pollen from flower to flower." And in a later letter: "I had no doubt that I could get all the information in regard to the varieties and his methods from his brothers, but I found that none of them were interested in peonies at the time of his death, and that none of his books or records were kept. I have been sorry many times that I did not get them at the time; they kept them for a short time and sold them for old paper."
Mr. E. J. Shaylor produced a number of fine varieties, but I have been unable to learn anything as to his procedure beyond a statement made to me by Mr. Winthrop Thurlow that he believed the blood of Lady Alexandra DufFhad gone into a good many of them. I made repeated requests to Mr. Shaylor for some account of his work, but he was quite obdurate about it, from which the inference may be drawn, if one chooses, that he probably had no definite records, no "secret" to impart.
Mrs. Pleas has given us, in her reminiscences published in the American Peony Society Bulletin No. 5 (1917), a succinct ac-
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count of the parents of her seedlings in the statement, "The white single, The Queen, is the mother and grandmother of every seedling peony I have produced." That is, her seedlings are all either first or second generation from that Kelway variety, itself, no doubt, a single drawn from a strain of doubles.
Mr. Rosefield has, from his own account in the above-mentioned issue of the American Peony Society Bulletin, used no precautions except to keep his collection up to a high standard and to gather seeds formed by natural means on his best sorts.
Mr. Winthrop Thurlow replied to my request that he should give me some information as to the methods which have been followed at the Cherry Hill Nursery, as follows:
We planted the seeds, which produced most of the seedlings which we have since catalogued, in the late 90*5, somewhere about 1898, and no attempt was made to procure hand-fertilized seed. In fact, at that time we paid very little attention to seed of a selection of varieties. Our father, T. C. Thurlow, had sold all of the peonies and he told us boys that if we picked the seed and planted it we might have the seedling plants. The result was that we gathered one-half bushel or more of seed, and these produced approximately 100,000 plants. Of course, the very large majority were mediocre, and we selected about 100 varieties for further observation. This number has been cut down from year to year as some of the varieties did not recover well after being divided, that is, did not recover quickly, and some for one reason or another showed defects as they grew older. . . .
I am inclined to think that if one could steer a middle course and collect a quantity of seeds from good varieties that he could make a small selection of some really fine varieties. I remember Mr. Farr telling me about iris, that his method of crossing was to plant in close proximity the varieties which he wished to cross, and allow the bees to make the pollination. With our peonies we cannot even approximate the parentage, and I suppose we should name them all "Topsy."
All this applies, of course, to the Chinese peonies which have been so successfully produced at the Cherry Hill Nursery. But I know that persistent efforts have been made there to get a new "break" by crossing the shrubby lutea with the albiflora varieties. If any success has followed the efforts in this direction, the public has not yet been informed of it. Lemoine and others have attempted this same cross, enticed thereto by the dream of securing a race of bright yellow, herbaceous peonies. But so far as I know, no one has anything to report but failures. The plant-breeder may well ask himself how long he should continue such efforts before the enterprise is to be considered
plate XXVII. Henry Avery
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hopeless. I once asked the able and experienced plant-breeder, Dr. A. B. Stout, when one might consider such proof complete. He replied "When your patience is exhausted."
Mr. A. M. Brand, in his interesting notes published in the American Peony Society Bulletin No. 6 (1918), makes it clear that he has relied on mass production for originating varieties of high quality. His statement that sixteen quarts of seed were sown at his nursery in 1917 illustrates better than many words what his method is, and would indicate also that we may expect further good things from him in the future.
Of other American growers who have come more recently into the field—Franklin, Judge Vories, Andrews, Good & Welsh, E.Auten,Gumm,and many more, I have no information.
Of late years the "fancy" is turning more and more to varieties of the Japanese type. These are charming as cut-flowers, and no less so as garden plants, for the blooms are so light that they can be adequately borne up with little or no artificial support, and thus the plants have a grace and beauty which is denied to most of the very full doubles, where the passion for producing gigantic, heavy flowers for exhibition has, in my judgment, worked against the quality of the plant for garden use. I presume some of those who are growing the Japanese type have used seed gathered from their own plants, but, no doubt, a good deal of the seed has come from Japan; and in that case our knowledge of possible parentage ends with the canvas bag in which the seeds were shipped.
Prof. C. S. Sargent, in 1893, wrote in Garden and Forest: "It is doubtful whether this plant can be further improved by cultivation although florists are adding every year dozens of new names to their catalogues." Many of the new varieties that have come out in the long interval since those words were written have gone to confirm rather than to disprove his judgment; but not all. Some of them show an improvement in form, some in color, over anything that existed among the Chinese peonies thirty-five years ago. Yet the type remains the same and in that sense perhaps one may say the peony has not improved. And still the peony grower keeps on; and if it should fall to the lot of one to produce a salmon-pink Therese or a cream-colored Le Cygne, all the efforts of twenty years would seem to the enthusiast to be amply rewarded.