Practically perfect maples - Japanese maples

Japanese maples add grace to small gardens. Here's a buyer's guide to the best varieties for northern climes

* IN ANCIENT JAPAN people would walk from their villages into the hills to view the delicate leaves and brilliant colors of their native maples. Over the centuries they brought the wild trees they liked best to their own gardens. By 1710, a writer named Ibei Ito had found 36 cultivated Japanese maples to include in his horticultural encyclopedia Zoho Chikinsho. Today there are more than 1,000 named varieties of Japanese maple (Acer palmatum), which are distinctive for their leaf shape, foliage color, or growth habit. Japanese maples grow in all Western climates except the coldest (Sunset climate zone 1). The trees reach near perfection along the Pacific Coast in places that are free from excessive heat, dry wind, and salty ocean breezes.

Characteristics to consider

The maples you see at the nursery will change as the season progresses. The following pointers and "A guide to Japanese maples," at right, will acquaint you with the characteristics of different trees.

Leaves often start out infused with red or purple, fade to green in summer, then color up again in fall. However, some leaves hold their spring color (be it green, purple, or red) until autumn, when they flush burgundy, scarlet, orange, or yellow before dropping.

* Laceleaf types, with deeply divided leaves, suffer more than most maples in hot, dry, and/or windy locations.

* Red-leafed varieties and the full-moon maples can handle more cold than other Japanese maples.

Bark can change color with the seasons. Coral-bark varieties develop the most color in winter on the sunny side of the tree. Green-bark varieties have good color year-round, showing deepest green on new twigs in summer.

Forms can be upright, spreading, or weeping; the weeping form often takes a distinctive mushroom shape.

* If you want a tree, buy an upright variety with a single trunk. If you prefer a shrubby look, choose one of the spreading varieties, which tend to have multiple trunks.

* Weeping varieties usually grow slowly, topping out in the 6- to 10-foot range.

* Laceleaf types are almost all grafted (the rootstock will be a plain maple species, while the top--the part that produces leaves and branches--will be a named variety from a different tree). The trunk will be straight below the graft, then start meandering and spreading above it, giving the tree a mushroom shape.

Planting tips

In your garden, Japanese maples will want a spot that gets about three hours of morning sun, then filtered shade during the warmest hours of the day. The hotter your summers are, the more crucial this balance of sun and shade becomes. When maples get too much sun and heat, laceleaf and variegated types scorch, while red-leafed varieties take on a burned bronzy sheen. At the other extreme, dense shade causes variegated, red- and golden-leafed varieties to turn green, and it mutes the color of winter bark.

Plant Japanese maples in the ground in loose, porous soil that affords good air and water penetration. To improve native soil, amend the backfill from the planting hole with an equal amount of organic matter (use peat moss if your soil is alkaline) and cover the root zone with an organic mulch to keep the soil cool and moist.

Since maples have abundant surface roots, they do well in relatively shallow and broad containers. Plant them in a high-quality potting mix.

The laceleafs

You can spur growth of all kinds of maples with an application of 5-10-10 fertilizer as leaves emerge in spring and in early summer. Potted plants need only one dose of controlled-release fertilizer in spring.

Water when the soil beneath the mulch dries out. Hard water is trouble, since it is usually accompanied by high pH and salts: Some gardeners use rainwater.

A guide to Japanese maples

These are the maples with deeply dissected leaves. Usually much wider than they are tall, and characterized by their mushroom shape, most trees have a weeping form that does a nice job cascading over rocks and walls. The delicacy of the leaves makes them vulnerable to heat, wind, and hard water, all of which can burn leaf tips and edges.

* Acer palmatum 'Filigree' (shown on page 104). Weeping; 7 feet. A classic green laceleaf, with very finely cut leaves. Yellow fall color.

* 'Garnet' (shown at left). Weeping; 10 feet. With fairly intense, nonfading leaf color, this is one of many good laceleafs in the red-to-purple range.

* 'Seiryu'. Upright; 25 to 30 feet. The only upright laceleaf, this has a distinctly feathery green look.

Variegated leaves

Whether their foliage is stippled, marbled, edged, splashed, or striped with white or cream, variegated types can illuminate a lightly shaded corner of the garden. But you have to be careful, since they can scorch in sun or hot winds and turn all green if you give them too much shade or fertilizer.

* A. p. 'Butterfly' (shown above). Upright; 7 feet. Scorch-resistant and nearly foolproof, this is the one to grow in borderline situations.