This section is from the book "Beautiful Gardens - How To Make Them And Maintain Them", by Walter P. Wright. Also available from Amazon: Beautiful Gardens: How To Make And Maintain Them.
Paeonies have risen rapidly to the front. Twenty years ago they occupied a modest position, somewhat comparable to that of Sweet Peas, and the two flowers have advanced together. In their modern, improved form there are few hardy plants more valuable than Paeonies. The flowers are of great size, borne well up above the foliage, embrace a considerable range of colours, and many are fragrant. But the value of the plants does not lie solely in their flowers. The stems, full of warm colour, make a very bright and cheerful feature in the spring, and later, when the foliage has fully developed, it is extremely handsome.
The Paeonies are divisible into two sections: (1) herbaceous, (2) tree or shrubby. The varieties of the former now grown in gardens have been derived principally, though not wholly, from the species albiflora and officinalis. The varieties of the other have come from the species Moutan.
Dealing first with the herbaceous section, the members of which die down annually, it may be said that although the species are not without beauty, the hybrids and varieties are so much superior for garden purposes that they may be relied on exclusively. This should certainly be the case in small gardens, where space is so limited that room can only be found for a few of the best. There is no border, however carefully selected its occupants may be, which will not be strengthened by the addition of a few plants. Bold clumps are as valuable for distant effect as Kniphofias, and are secured with as little difficulty, though somewhat more slowly.
The main flowering period is early summer, but a fair selection of sorts will probably give a prolonged flowering period. The plants never look finer than in partial shade. The colour of the rich, lustrous crimsons is deepened by shade, but this must not induce the grower to plant them immediately under large trees, especially greedy-rooted kinds like Elms, because it will be difficult, if not impossible, to work the soil as deeply as is desirable; and further, the tree roots will appropriate the manure.
Paeonies share with Roses - and, indeed, most other plants: - a strong liking for good fare. They love to dip their roots far down in a deep, rich soil; and, having got them there, to keep them. Frequent disturbance, which is all to the good with that class of herbaceous plants which make spreading stools with shallow roots (Michaelmas Daisies may be cited as an example), is altogether out of place with Paeonies, which do not form matted, expansive rootstocks with surface fibres, but produce strong, fleshy roots. Division is only needed every four or five years. They do well on heavy land, but by no means disdain light soil so long as plenty of decayed manure is used when planting, and provided that annual mulchings of manure are applied. Bastard trenching should be practised in order to deepen the root run, indeed, without it the manure would not do half the work of which it is capable.
Under a generous system of culture the plants will assume large proportions, consequently crowding must be carefully guarded against by thin planting. As a matter of fact, one good specimen is quite capable of producing all the effect desired at one particular spot, and it is far better, as well as more economical, to aim at an effect with one good plant than with a dozen poor ones. If, however, a clump or line is wanted, the plants may be put in a yard apart all ways.
Propagation is effected by division, but it should not be resorted to more often than is absolutely necessary, because the young plants do not make good, flowering plants under two or three years, as a rule.
The number of varieties is now so great that there is no small difficulty in making a selection. More economical than making out special lists from the catalogues is the plan of buying the sets which specialists offer at various prices. It does not follow that the lower-priced selections will be either bad plants or poor varieties. While scarce novelties must always be expected to be dear, the price of older varieties, which are more abundant and in less demand by novelty-mongers, tends to decline, in spite of the fact that they may possess every virtue that a garden plant should have.
Turning to the Tree Paeonies, the first point of difference from the herbaceous varieties that it is expedient to mention is a want of perfect hardiness. Although not to be described as tender plants, the young growths are the better for a little protection during late spring frosts. This may be provided in the form of cool stable litter. The method of propagation usually practised is also different. Pot roots of the herbaceous species such as albifiora and officinalis are grafted with scions of the Trees just below the surface, generally in August, and kept in cold frames.
Fig. A Good Tree Paeony.
Planting is best done early in autumn, as this gives the plants a chance of establishing themselves before winter. If in deep, rich soil, they may flower in the second spring, for they are mostly early bloomers, and should certainly do so well the third season. They are sometimes grown in pots, and forced gently into bloom, but it cannot be said that they are ideal pot plants. For the garden, on the other hand, they are magnificent. Like the herbaceous section, they give the best effect when they can delve well down into a deep, moist, fertile soil. On chalk or sand they will want well feeding with liquid manure, and good mulches, to give of their best.