Most amateur and professional fruit growers are less interested in plums than in other tree fruits. Perhaps I am prejudiced, but I feel that this is not fair to the plum. Plums yield some profit when rightly cultivated commercially, and no end of satisfaction when cultivated for the gardener's own entertainment. The large assortment of varieties which one may secure is in itself a claim to interest, and a source of much delight to the collector. The fact that different types of plums furnish fruit of very diverse characters makes the collection more valuable from every standpoint. So far as the writer knows dwarf plums have seldom been grown to any extent in America. They certainly have no present claim based on experience for recognition in commercial orchards. Nevertheless they have possibilities even for the growing of market fruit, and for cultivation in the garden, dwarf trees are altogether worth while.

In the chapter on propagation, reference has been made to the stocks used for plums and that subject need not be discussed here.

When plum trees have been secured budded on suitable dwarfing stocks, as, for example, Americana or sand cherry, they may be trained in a variety of ways. Probably the ordinary bush form is the best. Most varieties of plums do not form either a satisfactory pyramid or a strictly vase form. Some of the better growing Japanese varieties of plums approach the latter form fairly well. Red June, Satsuma, and Chabot may be mentioned as particular examples. With such varieties a true vase form can be maintained as well as with peaches. In dealing with a majority of varieties, however, a simple bush-like head without a mathematically constructed frame work is about the best that can be secured. In most cases the head should be formed low, preferably not more than six inches from the ground. Still considerable latitude has to be allowed the gardener's fancy in dealing with dwarf trees, and the writer can easily imagine a garden design which would require trees to be high headed. It would be practicable and excusable in some cases to form heads four, five, or even six feet from the ground. This is often done in England and Germany with all sorts of fruit trees, this form being referred to as a "standard."

A head can be secured at almost any point on a plum tree of good growth, by heading back at the desired height. Four to six branches should be allowed to grow the first year and in course of time these will be increased to eight, twelve, or even more. That is, there will be this number of what we might call main branches because they are all of approximately equal importance.

At the end of the first year after the tree has been headed back the main branches, which have now formed, are to be cut back in turn. With all strong-growing varieties it is best to remove from one-half to two-thirds of the annual growth from these main branches, if the tree is to be restricted to a comparatively narrow spread. A considerable number of strong shoots will put forth the next year. These should be thinned out as soon as they start to a number approximately twice that of the main arms. These new branches should be distributed as symmetrically as possible. The tree top is now formed and subsequent pruning consists essentially of a severe heading in during the latter part of the dormant season, that is, about March, followed by two, three, or four summer prunings somewhat after the manner described for the peach. At the time of these summer prunings the young growing shoots should be thinned out enough to prevent any choking of the tree top and should be headed in wherever it is necessary to retain the symmetrical growth.

The manner of forming the fruit buds or spurs is so diverse in the different kinds of plums that no general rule can be given for encouraging them. Close observation of each variety will soon enable the gardener to direct his pruning in such a way as to assist in this important process of fruit bud formation. In a rough general way it may be said that the Domestica and Americana varieties of plums form distinct fruit spurs along the sides of one and two year old branches, and that, for the encouragement of these, considerable light should be admitted and the growth of the interior shoots rather rigidly checked. The Japanese and Hortulana varieties on the other hand fruit best from very short spurs or clusters of buds which form along from the strong one and two year old branches. The main object, therefore, with these latter varieties is to maintain a succession of clean, sound, well matured shoots. This is done by a moderate thinning of the main shoots early in the year, resulting in the forcing of those which are left. These strong growing shoots are checked late in the summer in order that they may ripen up thoroughly, but the pinching which is done to this end is delayed long enough so that the pinched shoots will not start into growth again. Moreover, this pinching is done well out to the ends of the shoots.

Certain varieties of plums succeed fairly well as vertical cordons. The varieties least adapted to this purpose are the Hortulana offspring and their hybrids and a few of the rank-growing Japanese, like Hale and October Purple. In the dwarf tree garden at the Massachusetts Agricultural College the writer has a row of plum trees containing a large assortment of varieties and species. These trees were picked out at random from various sources and very few of them were propagated on dwarfing stocks. On this account the trees were set two feet apart, which is more than is usually recommended for upright cordons. They have now been growing three years, and they furnish much interesting testimony regarding the feasibility of growing plums in this form. Contrary to expectation such varieties as Red June, Abundance, and Burbank have done well under this treatment. These varieties all fruited the next year after planting. Some varieties of the Domestica group are bearing the third year after planting, which is unusually early. All of them seem to be fairly well adapted to this method of treatment. Varieties like Wildgoose and Wayland, and such hybrids as Gonzales, Waugh and Red May, can hardly be controlled in the restricted space allowed them in a row of vertical cordons. They give very little promise of success. It is probable that all these varieties would make a better showing if they were propagated on some such stock as sand cherry.

Plums are seldom—almost never—propagated as horizontal cordons. I have never yet undertaken it myself, but propose to do so at the first opportunity and with some expectation of moderate success with certain varieties. The slow growing sorts like Green Gage, Italian Prune, and Agen seem to offer special promise.

In the form of espaliers plums are often trained against walls. Indeed this is the favorite way of producing fancy plums in England, and the same practise prevails to a considerable extent on the continent of Europe. In this country walls are not required, and in most cases would be of no advantage. Where it is desired to cover back fences or sides of buildings, however, plum trees in espalier form can be confidently recommended. The Domestica varieties of highest quality such as Bavay, Jefferson, Victoria, Pond, Bradshaw, and Coe's Golden Drop would have first choice. The Japanese varieties can also be grown on trellises or walls, but the freer forms, such as the fan espalier used for the peach, are better suited to their habits of growth.

The following varieties of plums can be recommended for dwarf bush forms:

Such varieties of the Japanese class as Abundance, Chabot, Red June, Satsuma, Burbank may be grown on dwarf stocks in bush forms, but they are not altogether satisfactory. There are two objections against them: (1) It is difficult to keep them in restricted bounds, such a result being dependent on constant and severe heading in. (2) They overgrow the dwarf stocks very strongly and thus do not have a very firm hold on the ground. They are apt to blow over or break off after a few years, unless carefully staked up.

The following varieties can be recommended for upright cordons, in which form they will give moderate success if properly managed:

Also most of the clean-growing Americana varieties such as Smith, Terry, Stoddard, etc.

Mr. Owen Thomas recommends for growing on walls in England the following varieties: