Success in plum tree (Prunus domestica) planting and care requires deciding which variety of fruit the homeowner wishes to produce. Plums produce either cooking fruits or edible fruits. Many trees are self-fertile, others are moderately self-fertile and some require a pollinator to set fruit successfully. Because there are cold-hardy plum cultivars as well as cultivars that require a temperate environment, plums flourish across the United States. Sizes range from 30 feet in height to 20 feet. Espalier-style and bush-type plum trees are widely grown in gardens of limited space.
Prepare the planting site two weeks to one month prior to planting the plum tree. Mix organic matter such as peat moss or aged manure into the planting location. Till the organic matter deeply into the garden soil so its consistency is crumbly. The ideal ratio is 50 percent garden soil mixed with 50 percent organic matter in the planting hole.
Plant the plum tree in full sunlight. If the tree is grown in an area of harsh winters, locate the tree on the south side of a building to afford it with extra wintertime protection.
Dig the hole twice the size of the plum tree's root-ball. Place the tree gently into the hole. Firm the soil around the tree's root system to remove air pockets. Make sure the soil level sits 2 to 3 inches below the tree's bub union.
Apply 2 to 3 inches of mulch such as peat moss, bark chips or recycled plastic around the plum tree's base to help prevent weed growth and help the soil retain moisture. Do not allow the mulch to touch the tree's trunk.
Water the tree thoroughly. The plum tree needs to be kept moist, but not waterlogged, to establish itself.
Stake the plum tree to protect it from winds. Set the stake 3 to 4 inches from the tree's trunk. Use a stake that is as tall or slightly taller then the plum tree. Tie the tree to the stake using cotton rope every 8 to 10 inches. Tie the tree loosely. Occasionally check the tree to make sure the bindings do not become too tight as the tree grows.
Fertilize the tree in early summer and later summer using a 10-10-10 fertilizer. Apply 1/2 cup per tree, and water the fertilizer thoroughly into the ground.
Remove sucker growth as it appears. A plum tree grows an abundance of suckers around the tree's base from its root system. Tear the suckers out of the soil and discard. Sucker growth will not produce true plum trees because the suckers grow from the root stock the tree is grafted upon.
Thin plum fruits when they are four weeks old. Space the fruit 6 to 8 inches apart.
Prune plum trees lightly the first three years in June. Remove only a limited number of branches to allow air flow and light within the tree. As the tree grows, more pruning will be required depending on which variety the plum tree is.