Methley plums (Prunus salicina ‘Methley’), a Japanese variety, yield sweet, reddish-purple plums in U.S. Department of Agriculture plant hardiness zones 5 through 9. They grow from 15 to 20 feet tall and just as wide, and should be spaced at least 20 feet apart. Methley plums have a chilling requirement of 400 hours in order to yield fruit; hours of winter temperatures below 45 degrees Fahrenheit are chilling hours. If you live in an area that doesn’t meet that requirement, a Methley tree may not grow plums. They require no chores that are unusual for plums.
Methley plums require moist soil but will grow well in areas with low humidity and minimal rainfall. They need more water during the spring to autumn growing season and less water in the winter when they're dormant. When they're actively growing, they need enough water to keep the soil moist around the root zone. There is no formula for watering a Methley plum since sandy soil drains faster and dries out quicker than clay that retains water and remains moist longer. Hot weather will increase watering needs. As a home grower, the best you can do is watch the top of the soil. If it looks dry, dig down to check the moisture. As a rule of thumb, give young trees 2 gallons of water twice a week. Give mature trees up to 8 gallons of water twice a week.
Feeding Newly Planted Trees
Before leaves of newly planted trees appear in spring, spread 1 cup of 10-10-10 water-soluble granular fertilizer over an area 3 feet wide at the base of the tree and water well.
Apply 1/2 cup of calcium nitrate, 15.5-0-0, or ammonium nitrate, 34-0-0, over an area 2 feet wide in mid-spring and again in early summer.
Fertilize a Methley tree twice a year beginning the second year:
- In early spring, scatter 1 cup of 10-10-10 water-soluble granular fertilizer in a circle to match the spread of branches. Water well. After the second year, apply 1 cup for each year of tree age up to a maximum of 12 cups. Do not add fertilizer close to the tree trunk.
- In mid-summer, apply 1 cup of calcium nitrate or ammonium nitrate for each year of tree age. Provide up to 6 cups for older trees.
Pruning the Plum
Methley plums yield fruit in two to four years after you plant a nursery sapling. They begin the spring growing season by yielding flowers before leaves. Prune the tree after it flowers but before it has leaves the year after you plant the tree. Prune interior branches and damaged, diseased or dead wood. In addition, prune scaffolding branches -- the main branches that grow outward from the trunk -- to keep the center of the tree open to sunlight. Space the scaffolding branches evenly around the trunk and leave 1/3-inch stubs. This will help maintain plum yield and help control plant disease. Low, strong branches are typically selected for scaffolding branches because they making harvesting plums easier without using ladders.
You can maintain the height of the tree to 8 to 9 feet by allowing scaffolding branches to grow but pruning the upright center, including shoots that grow upright. Methley plum trees grow more plums on older wood as they get older, so pruning unnecessary new wood will improve yield
Possible Problem: Disease
Methley and Santa Rosa Japanese plums are more susceptible to bacterial spot of plum (Xanthomonas campestris pv. Pruni) than are European plums. This bacteria multiplies in warm rain with temperatures above 65 degrees F, causing spots on the tips and edges of leaves. The inside of the spots turn black and drop out, eventually causing defoliation of yellowing leaves. Severe infections can cause smaller plums with cracks on the surface. There is no chemical treatment for this disease. The best way to avoid it is to keep your tree healthy by making sure it has enough water, fertilizing it properly and pruning it when necessary.