Shade Trees
Few people would disagree that trees provide the best and most beautiful shade of all, but not everyone has the patience to wait for a small shade tree to mature. If there are already mature shade trees in your garden, count your blessings. It’s much easier to modify existing trees to meet your needs than it is to produce shade overnight.
Aside from having to wait for a tree to produce its desired effect, there are advantages to planting your own shade trees. Most important, you can be assured of having exactly what you want—the right size and kind of tree, deciduous, evergreen, flowering, or fruiting—and you can place it where it will provide the most benefit. The following pages are designed to assist you in the selection of the right tree. As most gardeners want maximum openness and brightness in winter and early spring, there are more deciduous than evergreen trees in the lists that follow. Since the purpose of these lists is to suggest trees for shading gardens, most of the trees described branch high, or can be easily pruned to do so, leaving ample room for gardening beneath them.
Since most modern gardens are small and trees often grow close to the pavement, foundations, and drainpipes, the majority of these trees have deep roots, if properly watered from the start. Most of them are reasonably clean. There is also a separate list of small-scale shade trees, most of which are adaptable to large containers in a terrace garden. Neither list is by any means exhaustive.
Ginkgo biloba (Ginkgo or Maidenhair Tree; Hardy to Zone 5) is deciduous. Its growth rate is variable but usually slow to 60 to 100 feet; it may grow 10 feet in 9 years. Usually conical in youth, it becomes open and wide-spreading as it ages, so that its shade is broken, not deep. It has no significant pests or diseases, and is tolerant of pollution. The fan-shaped leaves turn brilliant gold all at once, then fall quickly. This ancient tree dates back to the Jurassic period.
Gleditsia triacanthos inermis ‘Sunburst’ (’Sunburst’ Honey Locust; Hardy to Zone 5) is deciduous, and grows quickly to 35 to 50 feet. It is upright and spreading, forming a vase shape. It leafs out late and drops leaves early, making very light shade. It is tolerant of pollution and heat. The leaves are finely divided and golden, creating a lacy appearance; green forms are also available.
Liriodendron tulipifera (Tulip Tree; Hardy to Zone 5) is a deciduous tree, fast-growing to 70 feet or taller in a tall, pyramidal form. Its handsome, squarish, medium-green leaves make medium shade and soft-yellow autumn color. The flowers are beautiful but concealed in foliage. George Washington framed his view at Mount Vernon with a pair of tulip trees. Roots can be dense near the surface, so the tree needs deep watering; it is not drought-tolerant.
Metasequoia glyptostroboides (Dawn Redwood; Hardy to Zone 6) is a deciduous conifer. It grows quickly to 75 feet or higher, growing 35 feet in 10 years. It has a pyramidal form, and makes medium shade. Its bare form is beautiful in winter. Despite the great size of adult trees, the young tree is suitable for planter culture. Like the ginkgo this is an ancient tree, but rather new to American gardens.
Pinus thunbergiana (Japanese Black Pine; Hardy to Zone 5) grows quickly to 90 feet, much slower and smaller (but healthy) in hot, dry climates. It has a picturesque, irregular habit, and is very malleable—it can be pruned to any shape and kept at the desired size, even as a bonsai. The degree of shade it gives depends on shaping.
Pistacia chinensis (Chinese Pistache; Hardy to Zone 9) is deciduous, with a moderate growth rate to 50 to 60 feet and as wide. Its graceful, finely divided leaves make filtered shade and spectacular tones of red, orange, and yellow in fall. It has a short trunk and a zigzag branching pattern. It needs staking and shaping when very young. It has no particular pests or diseases, and thrives in wide range of climates, including extreme heat.
Quercus robur ‘Fastigiata’ (Pyramidal English Oak; Hardy to Zone 6) is a deciduous tree with a moderate to fast growth rate to 70 feet or higher. Its habit is columnar in youth, pyramidal in maturity. The lobed leaves make medium shade, and hang on until late in the season. Many other oaks, both deciduous and evergreen, are available regionally.
Robinia pseudoacacia (Black Locust; Hardy to Zone 4) is deciduous, with a fast growth rate to 40 to 75 feet. Its umbrellalike form, sparse and open, casts very light shade. Long, hanging clusters of fragrant white flowers appear in late spring among divided leaves. Although it is subject to some pests, this is one of the toughest trees, thriving in the poorest soils, under adverse conditions, and with complete neglect.
Sophora japonica (Japanese Pagoda Tree; Chinese Scholar Tree; Hardy to Zone 5) is deciduous, with a slow growth rate to 20 or 30 feet, then a moderate rate to 50 to 75 feet and as wide. Its dense, upright form in youth rounds and spreads with age. The large, lustrous, dark green leaves, divided into many leaflets, turn yellow in autumn. Clouds of white, wisterialike flowers bloom in late summer. Flowers and pods can litter walks and patios.
Zelkova serrata (Sawleaf or Japanese Zelkova; Hardy to Zone 6) is deciduous, with a moderate to fast growth to 50 or 60 feet and as wide. It is roundish as a young tree, vase-shaped as an older tree. The leaves are oval and serrated, very similar to those of the closely related American elm. It makes medium shade. Unlike the elm it is disease and pest-resistant, and the roots are not often bothersome, particularly with deep watering. Young trees need pruning to establish a proper framework.
