Soil.—All soils are good for the plum, provided they be thoroughly drained, and properly fertilized.
Hard soils are recommended as being almost proof against the curculio. That a soil affording a rather hard, smooth surface, will afford less burrows for curculio, and consequently lessen their ravages, is no doubt true. But it is not a perfect remedy, and, on other accounts, such a soil is no better. A good firm loam is best. Plums will do well also on light land, but are more exposed to injury from the curculio.
Transplanting.—The plum being perfectly hardy, we recommend transplanting in autumn. Shorten in the top, cut off considerable of the tap-root, and the ends of the long roots, transplant well, and mulch so thoroughly as to prevent too strong action of the frost on the roots, and they will start early and do well. Twelve feet apart for small varieties, and twenty feet for larger growers, are the distances usually recommended. We think a rod apart each way will do well for all varieties.
Pruning.—Once started in a regular growth, in such a shape as you desire, no further pruning will be necessary but occasionally heading-in a too luxuriant shoot, and removing diseased and cross limbs. On rich Western lands, and in warm Southern climes, young plum-trees must be root-pruned and headed-in, or they will be unfruitful and unhealthy. Root-pruning should be done in August, in the following manner. In case of a tree ten feet high, take a sharp spade, and in a circle around the tree, two feet from the trunk (making the circle four feet in diameter), cut off all the roots within reach. In smaller trees, make the circle smaller, and in larger ones, larger. At the same time, shorten in the current year's growth, by cutting off one half the length of all the principal shoots; this will give vigor, symmetry, and fruitfulness, and prove a valuable preventive of disease. Plum-trees should always have good, clean cultivation.
Manures from the stable and slaughter-house, with wood-ashes, lime, and plenty of salt, are the best for the plum. The following analysis, by Richardson, of the fruit of the plum, will aid the culturist in his selection of manures:—
| Potash | 59.21 |
| Soda | .54 |
| Lime | 10.04 |
| Magnesia | 5.46 |
| Sulphuric acid | 3.83 |
| Silicic acid | 2.36 |
| Phosphoric acid | 12.26 |
| Phosphate of iron | 6.04 |
Hence, as wood-ashes contains much potash, and as this is the largest ingredient in the plum, it must be the best application to the soil for this fruit. Bones, dissolved in sulphuric acid, would also be very valuable. Bones, bonedust, salt, wood-ashes, and barnyard manure, with a little lime, will be all that will be necessary.
Diseases.—In most northern latitudes, the black wart, or knot, is fatal to many plum-trees. It is less prevalent at the South: its origin is not known. Many theories respecting it are put forth by different cultivators; they are unsatisfactory, and their enumeration here would be useless. It may be either the result of general ill health in the tree, from budding on suckers and unhealthy stocks, and a want of proper elements in the soil, or of improper circulation of sap, caused by the roots absorbing more than the leaves can digest. In the latter case, root-pruning and heading-in would be an effectual preventive. In the former, supply suitable manures, and give good cultivation. In every case, remove at once all affected parts, and wash the wounds and whole tree, and drench the soil under it, with copperas-water—one ounce of copperas to two gallons of water. This is stated to be a complete remedy.
Defoliation of seedlings and bearing trees often occurs in July and August. Land well supplied with the manures recommended, especially wood-ashes, salt, and the copperas-water, has not been known to produce trees that drop their leaves.
Decay of the Fruit is another serious evil. Professor Kirtland and others suppose it to be a species of fungus. Poverty of soil, and wet weather, may be the cause. If the season be unusually wet, thin the fruit, so that no two plums shall touch each other. Keep the soil properly manured, and spread charcoal or straw under the tree, and you will generally be able to preserve your fruit.