Plums are one of the stone fruits like peaches, apricots and cherries. The more common fresh eating varieties are either European or Japanese, although the Japanese plums do not grow as well in the northeastern United States. Damson plums are mostly used for cooking and preserving, including the preparation of prunes. In spite of the varietal differences, plum trees all share common growth components.
Size and Age
Plum trees tend to be smaller than other fruit trees. Nursery saplings tend to arrive anywhere between three and six feet tall. At the high end, this is already half the height of a mature plum tree. Trees are considered mature when they begin to produce fruit. This typically happens at five to 10 years of age and continues for another 10 to 15 years. Mature trees reach a height of just 12 to 15 feet ,making them easy to harvest.
Plums thrive in deep, well-drained soils. They are more tolerant than other stone fruit trees are of waterlogged conditions and heavy soils such as clay. The soil pH should be between 5.5 and 6.5 for the best growth results. A soil test from your university extension can reveal the pH and suggest ways to alter the soil if necessary.
European varieties such as Stanley produce a few small, white flowers early in the spring, making them susceptible to late frost damage. Japanese plums produce an abundance of small flowers in clusters. They bloom later in the spring, making them less prone to frost damage. Bees are the primary pollinators of plum flowers.
Plums take anywhere from two and a half to six months to ripen, depending on the cultivar. Some Japanese varieties are ready in three months while the Damsons used for preserves can take well into fall. The best fruit growth is experienced when trees are thinned early in the growing season. This practice allows fewer fruits to develop but they are of better taste and quality. It also reduces the stress on the tree when it has fewer plums to support.
Other Growth Considerations
Plum trees are pruned in commercial settings with an open center to allow better air and light circulation. This promotes good health and vigorous growth. Regular inspections for disease and insects can help curtail the problem before the plum tree growth is affected. Regular watering, particularly during fruit production of varieties that are eaten fresh, enhances their growth. Do no over-water as this can cause cracking and spoil the fruit.