The "Bloodgood" Japanese maple (Acer palmatum "Bloodgood") is a deciduous shrub or small tree that is notable for the red leaf color it retains all summer. The maple grows up to 20 feet tall and should be planted in an area that it is protected from wind. "Bloodgood" maples grow best with light shade and a moist, well-draining soil. If the leaves drop outside of the normal time in autumn, the problem may be cultural or environmental. "Bloodgood" maples grow in U.S. Department of Agriculture plant hardiness zones 5 through 8.
"Bloodgood" Japanese maples leaf out early in the spring. If the winter was unseasonably warm, the tree may think it is spring and leaf out too early. Even if they leaf out on schedule, there may be a late cold spell in the spring. In either case, if there is a frost or freeze after the new leaves have emerged, the leaves may be damaged. They appear to wilt and then drop from the tree. If the tree is otherwise healthy, it may recover and grow new leaves. Protect new growth from spring frosts with a frost cloth.
Verticillium wilt is a fungal disease that affects many trees and plants, including the "Bloodgood" maple. The leaves appear to wilt or may turn yellow or brown. The affected leaves are isolated at first, and then spread along limbs and throughout the maple if left untreated. The dead leaves fall, making the foliage sparse. Check an affected limb for the disease by scraping a 1-inch section of bark from the branch with a knife. Dark stains in the exposed wood indicate verticillium wilt. Prune out infected limbs.
Too little water will stress your maple, causing leaves to wilt, brown and drop. In hot or dry weather, supplemental irrigation is necessary to keep the maple healthy. Water the tree deeply and keep the soil moist but not wet. Do not water at the base of the trunk, but water over the root zone and around the drip line to avoid trunk rot. If the top 4 inches of soil are dry, your tree can use some water. Adding a 2- to 3-inch layer of mulch over the root zone can help drier soils retain moisture. Do not overwater, however, as the maple will drown. Do not let the roots set in standing water.
Several types of caterpillars and larvae, such as the fruit tree leafroller (Archips argyrospila), feed on the leaves of maples and other ornamental and fruit trees. If the larval infestation is severe, the maple may be losing its leaves because they are all being eaten. Look for webbing and rolled leaves and holes in the leaves. Check undersides of leaves for caterpillars. If you see masses of eggs attached to the tree trunk, scrape the leaves into a container filled with water and dish soap. Clip and dispose of individual infected leaves or branch sections. Spray the foliage with a premixed spray containing Bt (Bacillus thuringiensis) to kill the larvae.