Oh, nothing could be finer than a plum in Carolina... or anywhere else, for that matter. In fact, plums rate just behind apples as the most popular homegrown fruit around. Not hard to figure - there are dozens of varieties available; they can be dried, stewed, baked, or picked ripe and bursting with sweetness and savoured on the spot.
Plums are classified into the three groups mentioned above: Japanese plums which are predominantly red; European plums which are predominantly blue; and native varieties that are usually red or yellow in colour.
European plums have a thick, firm flesh that make excellent prunes, preserves, or desert fruit. The fruit is very sweet and aromatic, and usually has an oval shape. These include prunes, green gages, and Damson.
Japanese plums are soft and juicy, with flesh that ranges from tart to sweet. These large, round plums are best eaten fresh, and not for drying.
Native or cherry plum hybrids (crosses of sandcherry and Japanese plum) have small, tart fruit, and are best used for making jams, jellies, and preserves. These plums are cold hardy and will survive in the prairies, although some may require winter protection.
Cultivation of European and Japanese trees is similar: Trees should be planted in full sun, in a neutral soil (pH 6.0 - 7.5). Acidic soil can be amended by the application of compost and a handful of lime at the time of planting.
European plums can take a heavier, well-drained soil, whereas Japanese and native varieties will tolerate a lighter, shallower soil.
Remove all perennial weeds from the planting site. This is the time to incorporate organic material such as compost, aged manure, or peat moss into the soil. Add a sprinkling of bone meal to the soil will be beneficial as well.
Ensure the planting hole is large enough so the root ball can be fully extended. For bare-rooted trees, spread the roots out, removing any damaged or broken roots. If the tree is container-grown and slightly pot bound (the roots have grown in a tight circle), break some of the dirt apart so the roots spread out.
Fill the hole with soil, firm it down, and water in well. Make certain the graft union of the tree is well above the soil level (3-4") or the scion may send out roots and take over, causing the tree to lose its dwarfing effect.
A layer of mulch will keep weeds down, and retain moisture. If suckers form, pull or cut them off at soil level. Plums blossom earlier than apple trees and can be damaged by a spring frost. Choose the best variety for your area. Japanese plums are particularly susceptible to frost as they are the first plums to flower. If spring frosts are a concern, plant the tree in a sunny, sheltered area and avoid planting in an area where frost may settle and damage the blossoms.
Many European plums are self-fruitful, but even these will set a better crop if there is another variety planted nearby. Most Japanese plums are not self-fertile and will require a cross-pollinator. Blooming periods must overlap as an early plum will likely not pollinate a later variety. However, a mid-ripening plum will pollinate the early and late-ripening trees.
Japanese and European plums cannot pollinate each other. Pollination for Native plums is another native variety, a sandcherry plum hybrid, and certain Japanese plums.
European plums bear fruit on long-lived spurs, Japanese plums bear fruit on spurs and also on new wood of the previous season.
Semi-dwarf and dwarf varieties are excellent for smaller, urban yards. Young trees are generally trained to an open centre or vase shape as this allows even ripening of fruit and good air circulation, which helps prevent disease.
European plums have a more compact growth habit and can be grown in an open vase form (the middle of the tree has no central leader), in an informal fan-trained shape, or in pyramidal shapes. Plum trees do not grow well in confined forms such as the cordon, which is better suited for apples and pears. Because of their lanky growth habit, Japanese plums do best kept to an open or pyramidal frame. Native or sandcherry plum hybrids are usually found in bush form, or as small trees.
Purchase a sturdy two- or three-year old tree from a nursery. Look for a tree that has three or four well-spaced branches growing upward and away from the trunk. If you purchase a year-old tree (known as a "whip"), the tree will require some form of support for the first two years.
Once the desired shape has been achieved, pruning will be primarily to maintain the framework of the tree, and to remove any weak or damaged branches. Branches that rub against each other should also be removed. In late summer the current season's growth can be trimmed back by a third or half. This will keep the tree compact and produce sturdier branches that can support the fruit. European plums grow less vigorously than the Japanese or native plums and require less pruning.
If trimming or pruning a larger branch, use a proper pruning saw and be certain to seal any cuts 1" or more in diameter. Check with your local nursery to see which sealants are available.
In certain years plums may bear an extra-large crop. Younger trees may require support so the branches don't break. If the crop is too heavy, size and taste of the fruit may suffer. Also, an extremely heavy crop may reduce next year's crop - too much fruit one year means less energy to produce flower buds the next year.
Remove some of the surplus fruit in early or mid-June, leaving fruit 3-4" apart for European plums (or one or two per cluster), and 5-6" for Japanese plums as they are regularly over-productive.
Plums in coastal areas are particularly susceptible to black knot fungus. This fungus is easily identifiable and may eventually weaken and kill the tree unless controlled. Cut and dispose of smaller, infected areas. Prune 3"-4" below the infected area, ensuring that your shears are dipped in alcohol before making another cut. This will avoid spreading the disease to other trees. If the fungus is on the trunk of the tree carve the area away until healthy wood is reached. Be certain to remove all pieces of the diseased wood.
The plum curculio can wipe out your plum harvest very quickly. The female curculio lays eggs in the plums - easily noticed by the crescent-shaped cut on the fruit. Fruit may become shrivelled and drop prematurely. The plum curculio overwinters in the soil, therefore remove all fallen fruit, and cultivate the soil to help break the cycle.
Brown rot can affect plums and other stone fruits. This fungus causes fruit to shrivel and mummify. Remove all infected fruit and dispose of it.
Spraying with dormant oil and sulphur, and practising good sanitation (removing diseased fruit, wood, etc.) will help keep other pests and diseases in check.
There's something very satisfying about growing your own fruit, which is why so many gardeners do it. If you have space in your yard, do plant a plum tree - your family will thank you for it.