Some people may desire to keep Japanese Maples smaller, especially the weeping lace leaf varieties, as they may be trained as a groundcover. Pruning can be done anytime from late October through Late June, although ideally when dormant in winter.
Japanese Maples are mostly pest free in our area, but they are sometimes attacked by chewing insects such as Japanese beetles or various caterpillars. If damage is noted, any pesticide with residual control, used as directed, works fine. Although not a pest or disease, scorching due to improper watering may cause disfiguring of the leaves.