The two most common varieties of plum trees are the Japanese (prunus salicina) and the European. The Japanese is the more widely grown plum tree of the two, bearing the Santa Rosa plums most often sold in grocery stores in the United States. This fast-growing, vigorous tree is not self-fertile; it requires more than one tree for pollination in order to bear fruit. The Japanese plum tree can reach a height of 12 feet. It's one of the earliest blooming fruit trees in late winter to early spring, with numerous fragrant, white flowers covering the branches.
Select an area that gets full sun daily and has warm temperatures; that's important for growing your Japanese plum tree. Being frost sensitive, Japanese plum trees are hardy in growing zones 6 to 10. The area should also be large enough to accommodate at least two trees planted together for pollination.
Prepare the soil as soon as it is workable in early spring. Amend with organic compost to give good drainage to the soil and add needed nutrients for the strong roots.
Dig a hole in the soil you have prepared, making sure the hole is three times larger than the root ball of the tree. The size of the hole will depend on the size of the root ball. When planting more than one tree, dig a hole for each tree spacing them about 20-feet apart. If planting rows of trees, the rows need to be at least 20-feet apart to avoid over crowding.
Set the tree into the hole with the top of the graft union about 3 to 4 inches above ground level. Fill in the hole half-way with soil, then water it, just until the soil is wet. If there is standing water in the hole, let drain before adding more soil. Finish filling in the hole with soil. This helps eliminate air pockets around the roots. Mound the soil slightly around the top of the root ball; firm over well with your hands.
Water your tree with a drip irrigation system, so that the tree receives a deep and thorough watering weekly. About one-inch of water weekly is usually sufficient. However, in warmer weather, watering more frequently may be necessary if the leaves begin to turn brown, which indicates the tree may be drying out too much.
Apply a balanced fertilizer of 10-10-10 in the early spring months and again in the early summer months. For each application, sprinkle a handful of fertilizer around the base of the tree and water in well.
Prune sparingly in the first couple of years to allow the tree to reach its potential growth; doing so will also help shape the tree by opening up the center. This is done by cutting out any branches that cross in the middle and by cutting branches that grow straight up in the center of the tree. Keeping the center of the tree open allows for better air circulation and sunlight to get to the branches, creating a healthier tree.