Japanese maples (acer palmatum) are deciduous trees that grow best in USDA zones 5 to 8, which include Connecticut, Rhode Island, Massachusetts and Vermont, as well as southern parts of New York, Maine and New Hampshire. They achieve heights and widths of up to 25 feet but do so with a slow to moderate growth rate. Japanese maples like moist, well-drained soil and light shade. As they grow, the species matures into a layered look, with a round top and spreading branches. In the fall, the leaves on Japanese maples in the Northeast turn purple, red, bronze or yellow. Prune Japanese maple to improve its health and shape.
Prune Japanese maple during the dormant, winter, season in the Northeast. The leaves have fallen off and you can best see the tree's shape and form. There will also be minimal damage at this time.
Remove lateral branches that grow downward, crossing into the scaffold whorl or layer of branches below it. Cut it where it meets the trunk. This will help the tree look layered.
Cut branches that are diseased, dead or damaged by harsh Northeast winters. Prune them just outside the collar, which is the thick section at the base of the limb. Healing will be best here and there will not be an unsightly stump left behind.
Trim off small branches that are clogging up the inside, top of the Japanese maple tree. They are blocking the sunlight and air from reaching the healthiest branches.
Get rid of branches that do not curve, taper or divide. They may be growing straight out from the tree, as opposed to growing in the natural wavy pattern other branches achieve. Cut them off at the V-shaped connection they share with another branch.
Saw off branches that are touching the ground or something else such as a roof. This messy growth ruins the appearance of a Japanese maple in the Northeast and blocks clearance below the tree. The branches can also pick up disease and infestation.