The Plum being one of the hardiest of fruits, many of its varieties are admirably suited for cultivation in the open ground. If a tall-standard form of growth be intended, the stronger-growing varieties must be fixed upon - the young shoot made the first season must be trained up to a stake, so as to keep it erect. If at the end of the season's growth it has attained the desired height and perfected its wood, so much the better; but if not, it ought to be cut back to the first plump bud upon the ripened wood, and the following year trained up to the desired height. If it takes two years to accomplish this, there will be a number of young shoots made upon the former year's wood; these, during the summer, ought to be regularly pinched back to three or four eyes, so as to throw strength into the leader. At the winter pruning these ought to be cut back entirely, so as to leave a clean bare stem. Standard Plums are grown at heights ranging from 3 to 5 or 6 feet. 4 feet is considered to be a very good height. To get this, prune the leader 2 or 3 inches higher; the following season three or four shoots can be had springing from the stem to form the young tree at the desired height. All other shoots made lower than this we would pinch as already hinted, and cut clean off at the winter pruning.

The shoots left for forming the tree should be cut back to about 1 foot in length, so as to get the tree well furnished, and avoid a long and straggling habit. In the case of a variety which has a tendency to grow very erect, the pruning should be done directly beyond a bud, in such a position as would tend to spread out the branches as much as possible. Where the habit is drooping, as is generally the case with plums, the point-bud left at the pruning season ought to be directly on the top of the shoots, in order to encourage a more erect habit of growth. The cultivation in all after-management of young standard-plums must be guided by circumstances, as well as taste in the formation of the trees, as it is impossible to give a pen-and-ink sketch which would be alike satisfactory to instructor and instructed.

Where dwarf-standards are desired, the weaker-growing sorts are best. After the first year's growth, the leader may be cut back to 15 or 18 inches, leaving three or four nice plump buds to form the young tree. These the following season must be cut back to about 1 foot, using the knife with discretion, and bearing in mind the rules already laid down.

I have never tried the Plum as a pyramid, nor have I ever seen it as such. From its general appearance and habit, and the mode of pruning and training necessary, it is my opinion that, grown as pyramids, it would not succeed. I may be wrong, but my idea is, that as such it would be far more likely to make such growth as would result in the production of wood in place of flower-buds. If any one has grown the Plum in that way, and succeeded, it would give me much pleasure to receive their experience through the pages of the 'Gardener.'

No matter whether as a tall or dwarf standard, the Plum is much benefited by a regular course of root-pruning. As I have said so much upon this point when speaking of the Apple and Pear, it is only needful to say that it is necessary, and may be commenced when the young tree is two or three years of age, and continued regularly, at intervals of two or three years, for a considerable length of time. Great care must, however, be taken to dress neatly with a sharp knife every root that is cut, so as to avoid, if possible, anything that would tend to encourage canker, or the effusion of gum - the two great enemies of the Plum cultivator. When this operation is performed, a little fresh material, such as I shall presently recommend to Plum cultivators, ought to be introduced round the trees; and should the winter be severe, or the following summer very dry, it will be found of great advantage to give each tree a liberal mulching with good stable manure. This, in fact, is a very safe practice, and may with advantage be adopted under any circumstances.

The best time to perform this operation is in September or October, although, if care and caution are exercised, it may with even greater advantage be performed in August upon such trees as may not be bearing a crop of fruit.

The soil which appears best to suit the Plum is a good strong loam, although in its natural state it is generally found in light and dry soils. When cultivated in soils of this description it flowers freely, but sets its fruit badly, and the fruit is generally small and poor in flavour. The best-flavoured and most handsome fruit is generally to be obtained from trees planted in good, strong, and moderately rich loam, which has been well drained, yet is not too dry. In soils of this nature it has been found, both in this country and in America (by Downing), that the trees are more secure from the attacks of insects than in soils of a light and sandy nature. Although the roots of the Plum do not penetrate to such a depth as those of the Pear or Apple, it is nevertheless of great advantage to have a good deep soil for it: in such a position it will not be likely to Buffer so much from the effects of a dry season as it would in a shallow soil. Where the soil of the garden is found to be of too light a nature, it would be wise to introduce a quantity of clay or very heavy loam to mix with it, or, what would be better still, to procure a quantity of good strong loam, removing the old, and replacing it with the new at planting time.

With this may be incorporated a moderate quantity of decayed stable or other manure. A little wood-ashes or charcoal, and a few crushed bones, may with advantage be added to the whole. As already hinted, excess of dryness or moisture is often injurious to the Plum, being frequently the cause of gum exuding, as stated by Thompson in his 'Gardener's Assistant.' To obviate this, it is necessary to have the ground drained, but not over-drained; and, if the soil be shallow, to have recourse to mulching in dry seasons.

The distance apart at which Plums ought to be planted will require to be regulated by circumstances, similarly with what has been stated in regard to the Apple and Pear. When planted against walls, the distances may vary from 12 to 24 feet, or even in some cases 30 feet, according to the height of the wall, and the sorts that are grown. In wall cultivation, the size and flavour of the Plum are often increased, and in proportion to the position given are these qualities still further developed. The Plum, being very hardy, is often placed in a north or eastern aspect; and although we have seen good crops and good qualities of fruit obtained from trees in these positions, nevertheless a more favoured aspect will be more satisfactory. It is impossible to provide a southern aspect for everything; yet, if it be at all possible, I would recommend that some of the finer varieties - such as Coe's Golden Drop, Green Gage, and such like - be placed in this position, as they will not only be earlier, but also of finer quality, of larger size, and more beautiful in appearance.

In planting Plums in the open garden or orchard, the distances for dwarf-trained trees may range from 12 to 18 feet, and for standards on high stems that are intended to form large trees, the distances may range from 18 to 30 feet, according to the size intended. In all cases of fruit-tree planting, I would earnestly impress upon every one to stake each tree neatly and securely, as nothing is more injurious to newly-planted trees than to be tossed to and fro by every wind that blows, or "every breeze that moves the midnight air".

The diseases to which the Plum is subject are only two, so far as we have been able to ascertain - viz., canker and gum. The former of these is generally the result of a wet and uncongenial climate; the latter is generally caused by wounds made by the rubbing of wall nails, or injury to the bark by the breaking and bruising of it by the hammer, or by being cut by string, shreds, or suchlike, and then neglected. If these things be regularly attended to, and the soil and climate prove to be at all congenial, there is little danger to be dreaded from either of these diseases until the trees advance into old age.

The insect enemies of the Plum are not nearly so numerous in this country as on the Continent, and more especially in America, where it is said "their attacks are so formidable as almost to discourage its cultivation in some parts of the United States." The most common enemies of the Plum in this country are black and green aphides, thrip, and red-spider. As I have already given recipes for the destruction of these, in the articles on the Apple and Pear, it is not necessary to reproduce them here. The curculio tenebricosus, or apricot weevil, as it is sometimes called, is frequently injurious to the Plum in old gardens. In winter it is generally to be found in the old nail-holes or crevices of the wall, where they lodge in numbers. The best way to get rid of them is to get the walls freshly pointed, so as to bury them over with the mortar, from whence they cannot escape. They are also to be found under the loose bark of the tree, when bark and all should be removed and burnt. After this the tree may be washed down with hot water, and a portion of the soil removed and burnt, so that those which may have fallen to the ground may be destroyed.

Tortrix Woeberiana is a small brown moth which often proves very injurious to the Plum, and is not unfrequently the cause of gum exuding. It penetrates to the inner bark when in its caterpillar form, and feeds thereon. From the wound made the sap escapes, and the result is often the formation of gum. Their presence is easily ascertained by the appearance on the larger branches and trunk of a reddish dust. Where this is deposited, the enemy is sure to be at work. By thrusting a needle into the holes made on the branches the grub will be destroyed, and painting the branches with a solution of lime in May and September has been recommended for destroying the eggs.

Tenthredo morio, or Plum saw-fly, is destructive to both fruit and flowers, depositing its eggs upon the calyx of the latter; while the larva, as soon as hatched, penetrates into the interior of the fruit, and, feeding thereon, causes it to fall off, after which it buries itself in the ground till spring, when it reappears as a moth. Gathering the fruit as soon as it falls and destroying it will be found the best means of getting rid of this pest. James M'Millan.

(To be continued).