How to Grow Plums in Tennessee

Test the soil pH in an area open to partial or full sunlight, such as the east-facing side of a house, at least six months to advance of planting plum trees. Tennessee soil tends to consist mostly of acidic clay, so you need to add about 8 pounds of ground limestone per 100 square feet to raise the pH one full point. Plum trees do best with a pH between 6.0 and 6.5.

Condition the soil with 2 to 3 inches of matured compost about three months before planting the plum trees or just before the first freeze of the year. Condition a 4- to 6-foot-diameter circle of soil for each tree.

Work the soil to a depth of 12 inches in late winter, typically between mid-February and the beginning of March, using a spade fork for the task. Use a tiller if the ground proves too hard to work manually.

Plant the bare-root plum trees in holes just deep enough so the graft union – the ridge that forms on the trunk where the scion and rootstock grew together – is 2 inches or less above soil level. Space the trees 18 to 22 feet apart.

Saturate the root system after planting, moistening the soil to the bottom of the hole. Water the plum trees with 1 inch of water weekly if your area of Tennessee receives less then 1 inch of weekly rainfall.

Prune the tip of the plum tree’s central leader to between 24 and 30 inches above ground level after planting, using pruning shears for the task. Remove 4 to 6 inches of the plum tree’s central leader if the tree measures less than 24 to 30 inches tall at planting.

Pinch back all the shoots growing from the central leader, except the four healthiest, to 4 to 6 inches long in mid-April after planting. The four healthiest shoots serve as the primary scaffold.

Prune any scaffold branches that cross over one another when the plum tree goes dormant in winter after the first growing season. If necessary, bend the branches slightly downward to train them to grow outward, as plum branches tend to grow vertically.

Pinch or prune all branches growing from the four primary scaffold branches, except for three of four of the healthiest, after the threat of frost passes in spring of the second year.

Prune the vigorous shoots growing in the center of the tree to the branch collars to open it up during the second year dormant period, using pruning shears for the job. Prune back one-third to one-half of all fruiting branches.

Sprinkle 1 cup of soluble, slow-release, 10-10-10 NPK fertilizer over a 3-foot-diameter circle around the plum tree, keeping a distance of 10 inches from the trunk on all sides, six weeks after the initial planting. Fertilize with 1/2 cup of 10-10-10 NPK fertilizer again in early June and a third time in early August.

Fertilize in early March and early August of the second and subsequent years, using 1 cup of 10-10-10 NPK fertilizer for every year of tree age. Apply the fertilizer over a 3-foot-diameter circle around the trunk but don’t worry about maintaining a 10-inch distance from the trunk when fertilizing mature plum trees.

Wrap a light-colored, 18- to 20-inch-tall trunk guard around the plum tree and secure it with wire ties just before the first hard freeze of the season. Bury the trunk guard 2 inches deep in the ground and leave it in place until the threat of frost passes in spring.

Check the plum trees regularly for soft, brown spots on the fruit, powdery tan spores, and flowers that brown early or wilt, all signs of brown rot fungus. Remove all infected plums from the tree and the ground at the first signs of brown rot fungus, and prune all diseased, damaged or dead branches.

Mix together 4 teaspoons of concentrated 29.7 percent calcium polysulfide spray with 1 gallon of water in a pump-type sprayer if the plums have brown rot. Spray the foliage and blossoms until covered, applying every seven to 10 days as needed.