The purple-leaf plum, also known as Thundercloud cherry plum, is a flowering deciduous tree with dark purple leaves. The tree is hardy to grow in USDA growing zones 5 through 9 and should be planted in full sunlight to maximize the purple leaf color. Purple-leaf plum trees produce 1-inch long pink flowers in spring before the leaf foliage is present on the branches.
Select a planting location for the purple-leaf plum tree that has a well-draining acidic soil and full sunlight conditions. A loam, loamy clay or sandy loam soil works well for the tree. Test the soil pH to verify it is 4.5 to 7.5. Mix ground rock sulfur into the soil two weeks before planting to lower the pH number. An acidic soil helps the leaves keep a rich color.
How to Plant
Dig a hole for the purple-leaf plum tree that is a two to three times the width of the root ball and the same depth. Mix organic compost and phosphorous fertilizer into the removed soil to increase the nutrient value and water-draining properties. Set the tree into the hole, making sure the top of the root ball is even or slightly higher than ground level. Fill half of the hole with amended soil and generously apply water. Verify the tree is standing straight and fill the remaining hole with soil. Gently pack soil around the root ball to eliminate air bubbles. Water the tree well after planting to an absorbed depth of 10 inches.
Care and Maintenance
Water the purple-leaf plum tree to a depth of 10 to 14 inches every other week during the hot summer months or during periods of drought. Fertilize established trees with a balanced fertilizer in spring before the main flush of growth. Apply a 2- to 3-inch layer of mulch around the tree to prevent weed growth and retain moisture. Leave a 6-inch gap between the start of the mulch and trunk of the tree.
Propagate the purple-leaf plum tree by taking softwood cuttings from late spring to early summer. Softwood cuttings are stem sections taken from current year growth that is green and flexible. Dip the cut end of the stem in rooting hormone and stick into a rooting tray filled with sterile rooting medium. Water the medium, cover the tray with a clear plastic bag and place the tray in a warm location until the roots reach 1 inch long. Transplant the cuttings into 4-inch individual growing containers and grow indoors for the first year.
Monitor the purple-leaf plum tree for the presence of borers or aphids. Borers tunnel under the bark of the tree and create deep grooves in the wood. Apply an insecticide to treat a borer problem. Aphids are small insects that appear on the leaves of the tree but cause no damage. The insects leave a sticky residue on the leaves and can be removed by spraying the tree with a sharp stream of water to knock the insects off. Prevent insect problems by keeping the tree healthy with adequate water and fertilizer applications.