How to Manage and ID Japanese Maple

How to Manage and ID Japanese Maple Japanese maple is one of the most versatile trees for any yard, patio, or garden. Often grown for its unique 7-palmed green or red colored leaf, the maple also has an interesting growth habit, with a fine leaf texture and muscular-looking multiple trunks. Japanese maples have extraordinary fall colors that range from bright yellow through orange and red, and is often striking, even on trees grown in total shade. Specifics Scientific name: Acer palmatum Pronunciation: AY-ser pal-MAY-tum Family: Aceraceae USDA hardiness zones: USDA hardiness zones: 5B through 8 Origin: not native to North America Uses: Bonsai; container or above-ground planter; near a deck or patio; trainable as a standard; specimen Availability: generally available in many areas within its hardiness range Physical Description Height: 15 to 25 feet Spread: 15 to 25 feet Crown uniformity: symmetrical  canopy  with a regular (or smooth)  outline  and individuals have more or less identical crown forms Crown shape: round; vase shape Crown density: moderate Growth rate: slow Texture: medium Foliage Descriptions Leaf arrangement: opposite/subopposite Leaf type: simple Leaf margin: lobed; serrate Leaf shape: star-shaped Leaf venation: palmate Leaf type and persistence: deciduous Leaf blade length: 2 to 4 inches Leaf color: green Fall color: copper; orange; red; yellow Fall characteristic: showy Popular Maple Cultivars There are many cultivars of Japanese maple with a wide variety of leaf shapes and color, growth habits, and sizes. Here are some of the most popular: Atropurpureum - has reddish leaves with only five lobes  Bloodgood - new foliage is bright red, some leaves darkening to a dim green  Burgundy Lace - reddish foliage with cut leaf (sinus nearly down to the petiole)Dissectum - finely dissected leaves in green or red, growing 10 to 12 feet tall  Elegans - leaves with rose-colored margins when they first unfold  Ornatum - leaf is beautifully cut and reddish Trunk and Branch Descriptions Trunk/bark/branches: bark is thin and easily damaged from mechanical impact; droop as the tree grows, and will require pruning for vehicular or pedestrian clearance beneath the canopy; routinely grown with, or trainable to be grown with, multiple trunks; showy trunk; no thorns Pruning requirement: requires pruning to develop a strong structure Breakage: resistant Current year twig color: green; reddish Current year twig thickness: thin Pruning a Maple Most maples, if in good health and free to grow, need very little pruning. Only train for developing a leading (or multiple) shoot(s) which will eventually establish the trees framework. Maples should not be pruned in spring and could bleed profusely. Wait to prune until late summer to early autumn and only on a young tree. A habit should be encouraged in which the branches develop low and grow up at sharp angles. If suckering of green-leaved root stock occurs below the graft line on your red-leafed grafted variety, remove the green sprout immediately. Japanese Maple Culture Light requirements: tree grows best in part shade/part sun but can also handle the shade. Soil tolerances: clay; loam; sand; slightly alkaline; acidic; well-drained Drought tolerance: moderate Aerosol salt tolerance: none Soil salt tolerance: moderate Common Pests Aphids can infest Japanese maples and heavy populations can cause leaf drop or a dripping of honeydew. Scales can be a problem. Neither insect will cause the tree to die. If borers become active, it probably means you have an already sick tree. Keep the tree healthy. Leaf scorch  may become a problem during periods of high temperatures accompanied by wind. Planting Japanese maple in a bit of shade will help. Keep trees well-watered during dry periods. Symptoms of scorch and drought are tan dead areas on foliage. Bottom Line The growing habit of a Japanese maple varies widely depending on cultivar. From globose (round or spherical form) branching to the ground, to upright to vase-shaped, the maple is always a delight to look at. The globose selections look best when they are allowed to branch to the ground. Be sure to clear all turf away from beneath the branches of these low growing types so the lawn mower will not damage the tree. The more upright selections make a nice patio or small shade trees for residential lots. A large selection or compact cultivars make wonderful accents for any landscape. Japanese maple tends to leaf out early, so it may be injured by spring frosts. Protect them from drying winds and direct sun by providing exposure to partial or filtered shade and well-drained, acid soil with plenty of organic matter, particularly in the southern part of its range. Leaves often scorch in hot summer weather in USDA hardiness zones 7b and 8, unless they are in some shade or irrigated during dry weather. More direct sun can be tolerated in the northern part of the range. Be sure drainage is maintained and never allow water to stand around the roots. The tree grows fine on clay soils as long as the ground is sloped so water does not accumulate in the soil. It responds well to several inches of mulch placed beneath the canopy.