Texas A&M University horticulturists recommend Japanese plums (_Prunus salicina_) rather than European plums (_Prunus domestica_) for cultivation in Texas, as European plums require colder climates than are found in Texas and are susceptible to brown rot and other fungal diseases.
Winter chill hours are hours of winter temperatures below 45 degrees Fahrenheit or a longer period of hours with temperatures averaging 45 degrees F necessary for plum tree to break dormancy. Once the winter chill hours are met, the tree will break dormancy and prepare for the spring to autumn growing season.
European plums require 800 to 1,100 hours at temperatures from 32 to 45 degrees F, or five to six weeks at a 45 degree F average. Japanese plums need only 700 to 1,000 hours from 32 to 45 degrees F, or four to six weeks at temperatures averaging 45 degrees F.
Japanese plums are self-fruitful, meaning they grow plums if they are planted by themselves, but they will yield more plums if they are planted with another Japanese plum cultivar for cross-pollination. Most Japanese plums will grow in U.S. Department of Agriculture plant hardiness zones 5 through 9, although some cultivars may vary.
Best Varieties for Texas
Texas A&M horticulturists recommend these standard-sized Japanese plum varieties for growing in Texas.
- 'Methey' (Prunus salicina 'Methey,' USDA zones 5 through 9) is adapted to climates throughout Texas. It yields small to medium-sized, sweet, flavorful purple plums that ripen in late spring. 'Methey' is self-fruitful but will yield more plums if it is cross-pollinated with another Japanese plum. It pollinates easily.
- A popular plum that grows throughout Texas, 'Santa Rosa' (Prunus salicina 'Santa Rosa,' USDA zones 5 through 9) yields large, purple plums that ripen in late June.
- A large, red plum, 'Bruce' (Prunus salicina 'Bruce,' USDA zones 6 through 8) needs pollen from a compatible tree to bear plums; 'Methey' is most often used. 'Bruce' Ripens in late spring.
- 'Morris' (Prunus salicina 'Morris,' USDA zones 5 through 9) will only grow in parts of Texas with 800 or more hours of winter temperatures below 45 degrees F. It yields more plums if it is planted with another Japanese plum for pollination.
- A self-fruitful tree that ripens in late spring, 'Ozark Premiere' (Prunus salicina 'Ozark Premiere,' USDA zones 5 through 9) yields large red plums with yellow flesh.
Planting and Locating
Plant bare root nursery trees from January 1 through February 15 and trees in containers from January 1 through March 31.
Plant plum trees in a spot where they get sun all day. Plant standard-sized plums, typically 18 to 20 feet high and just as wide, about 18 feet apart. Plums like sandy loams or other loamy soils with a soil pH between 6.5 and 7.0. If the soil doesn't drain well, plant the tree on a mound at least 6 inches high and 5 feet or more wide.
Watering and Fertilizing
Water plum trees enough to keep the soil consistently moist throughout the root zone -- but not soggy -- during their spring to autumn growing season. Give a small tree about 2 gallons a week and a large tree up to 8 gallons during dry weather. This is no one-size-fits-all watering formula for all conditions. Hot weather will cause the soil to dry out more quickly. Feel the soil with your hand a couple of inches down; if it feels and looks dry, it needs water.
Do not apply fertilizer when you plant plum trees. Give your tree roughly 1/2 pound of 10-10-10 water-soluble, granular fertilizer for each year of the tree's age, up to 6 pounds for a mature tree.
Begin with bud break in the spring after you plant the tree. Scatter the fertilizer in a circle around the tree extending 1 foot from the trunk to the spread of its branches, and water thoroughly. (See Reference 15) Break the year amounts in three applications, once after the tree breaks buds in the spring and again in late spring and late summer. (See Reference 14)