Customers want trees for shade. Sure, they’re interested in height and in all sorts of fancy ornamental characteristics, but if they’re buying a large tree, the primary reason is the cooling, protective effects of shade. The specific purpose may be energy savings or balance in the landscape, protection of a hardscape element or shelter for kids and wildlife. Shade trees, even on ever-shrinking properties, are standards in the landscape.
We’ve highlighted here five selections, each with its own ornamental and environmental value. Do you have a particular favorite?
1. Acer species
Let’s begin with a good old maple. For exceptional shade and outstanding fall color (and for syrup — hello, Vermont!), you just can’t go wrong with Acer. But with so many species, which to choose? Steer clear of Acer platanoides (Norway maple), whose reputation for aggressiveness has earned it a spot on invasives lists nearly everywhere. And for our purposes here, let’s not consider Acer palmatum (Japanese maple), whose short stature makes for a lack of sufficient shade.
Acer rubrum (red maple) is a glorious choice for a shade tree, easily grown in average soils, cold hardy down to Zone 3, delivering shade in summer and breathtaking color in fall. Generally reaching 60 to 70 feet tall with a spread to about 50 feet, it grows a bit faster than sugar maple (A. saccharum) but slower than the brittle — and not recommended — silver maple (A. saccharinum).
Emerging new growth, including leaves, leaf stalks, twigs and flowers are either red or blushed with red. Leaves, (which can be between 2 and 5 inches long) during summer are medium to dark green (with a grayish green underside) until they burst into flame in the fall. And the fruit — the two-winged samara kids call helicopters — is a brilliant red when it emerges, then turns tan to brown before each whirlygig flutters to the ground.
Acer saccharum (sugar maple) needs little introduction: It’s the hardwood that famously paints New England hillsides in fall. Typical height is 40 to 80 feet, with a 30- to 60-foot spread. This species, too, is easily grown in average, well-drained soil in full sun to part shade, and is hardy in zones 3 to 8.
Sugar maple, however, does not like compacted soils, and does not fare well in urban pollution or when exposed to road salt. But for shade on a residential, commercial or parkland property? It’s a winner.
Medium green leaves span 3 to 6 inches, turning to tones of yellow, orange, red and russet in fall.
Maples experience few insect or disease problems, provided appropriate cultural practices are observed.
2. Ginkgo biloba
Reputed to be the oldest tree around, Ginkgo biloba (maidenhair tree) has been called a living fossil, with evidence in the form of leaf fossils dating back about 270 million years. But the stately tree is no doddering dinosaur. On the contrary, the tree has experienced a resurgence in popularity in the past few decades owing, in part, to the promotion and sale of male specimens over female.
Yes, the tree is dioecious (separate male and female trees), and the female has a well-earned bad reputation. Females produce seed that is encased in fleshy, fruitlike coverings that, while slightly ornamental if they’re still on the tree, are noxious once they drop in the fall. Anyone who has strolled along a campus quadrangle in an autumn reverie and has been unfortunate enough to crush the fruit beneath a sandalclad foot knows the horror of the rank, putrid odor these fruits emit. “Gag-inducing” is putting it mildly.
So the industry has done an admirable job of concentrating on developing and selling male trees, much to the delight of the public.
Among the ginkgo’s most distinguishing features is its unique, fan-shaped foliage. In the slightest breeze, the foliage dances and shivers to rival any quaking aspen. Ranging from slightly to dramatically lobed (the specific epithet biloba meaning “two-lobed”) each 2- to 3-inch leaf emerges a rich green and matures in fall to a dramatic golden yellow. In the transition, leaves may bear streaks and blotches or interesting, almost ombre effects of green and yellow, as if each was dipped in a contrasting color. In full autumn glory, the tree is a breathtaking focal point.
The straight species can grow to about 100 feet tall by 40 feet wide, but cultivated varieties normally top out at about 50 feet with a spread of 30 to 40 feet. It requires very little special care in zones 3 to 8, preferring full sun and medium moisture. Deer and air pollution tolerant, Ginkgo biloba makes an outstanding landscape specimen and a sturdy street tree. It also has been recommended for use in areas requiring fire-wise landscaping.
Ginkgo suffers few insect or disease problems and is considered a low maintenance tree. It can be somewhat slow growing, but its versatility in a variety of locations and its ability to provide welcome shade are outstanding selling points.
3. Liriodendron tulipifera
Among the largest of our eastern North American native trees, Liriodendron tulipifera (tulip poplar, tulip tree) distinguishes itself in size, foliage and flower. (A member of Magnoliaceae, it’s not a common magnolia.) Mature height can reach 90 feet, and the tree can spread up to 50 feet, providing ample shade in any setting. It tolerates part shade but prefers full sun, and performs best in moist, organically rich, well-drained soil (it’s not very tolerant of drought). This tough tree is hardy in zones 4(5) to 9.
Despite its kinship with magnolia, the distinctive flower and foliage of tulip poplar easily identify it. Very showy, cupshaped, tulip-like, yellow flowers bloom in spring; flowers feature an orange band at the base of each petal, giving the bloom a painterly appearance. Unfortunately, the 2-inch flowers may be slightly camouflaged on much larger trees, because they emerge after foliage and may remain hidden above the leaves on upper branches until petals start to fall. Blooms are followed by dry, scaly, cone-shaped fruits that bear winged seeds. These persist throughout winter, providing an odd but interesting ornamentation.
Foliage is rich, glossy green on the upper side and a pale, flat green underneath. The unique, four-lobed, flat-topped shape can grow from 3 to 8 inches long and wide. Leaves remain clean through fall, when they turn golden yellow.
Because of its size, L. tulipifera is not recommended for use as a street tree, but given the appropriately sized property, this tree will reward with cooling shade.
Tulip poplar is not bothered by serious insect or disease problems.
4. Tilia cordata
Littleleaf linden (also little-leaved linden; Tilia cordata) is an excellent urban shade tree due to its ability to withstand polluted environments. Tough and sturdy, it’s often used as a street tree but performs well in a variety of locations. Reaching 60 to 70 feet tall with a spread of 30 to 40 (up to 50) feet, this drought-tolerant selection is easily grown in average, welldrained soil in full sun in zones 3 to 7.
Three-inch-long, shiny, dark green, ovate to cordate leaves persist through autumn, turning a somewhat unremarkable yellow before falling. The tree’s unusual, early summer flowers, however, are showy and fragrant. Small clusters of creamy yellow flowers appear in dangling cymes, and they bloom in such abundance that the tree may be covered in a haze of delicate color and rich scent. Flowers are bee magnets, and often the trees can tremble with their activity.
Flowers morph to nutlets attached to long, narrow, bractlike wings that decorate the tree like ornaments. The nutlets ripen and mature in late summer; when bracts fall, the litter may be considered by some to be a bit unsightly. (Then again, so are the piles of leaves deposited by any deciduous tree.)
Littleleaf linden seems not to be bothered by significant insect or disease problems, although if there is dramatic Japanese beetle pressure in the immediate area, linden may be susceptible. Typical pest management practices will suffice.
There are a number of cultivars available on the market, each with slightly different ornamental or size characteristics.
- T. cordata ‘Chancellor’ is more compact than the species, reaching about 50 feet tall; its young habit is upright, turning more pyramidal with maturity.
- Corinthian® (T. cordata ‘Corzam’) produces a narrower pyramid, formed by a straight central trunk. It reaches about 45 feet tall with a 15-foot spread.
- T. cordata ‘Greenspire’ also is a shorter version of the species, growing to about 50 feet tall and producing a neat pyramid shape.
- Shamrock® (T. cordata ‘Baileyi’) is similar to Greenspire, but produces a more open crown, spreading to about 30 feet wide.
- Summer Sprite® (T. cordata ‘Halka’) is a compact selection with a rounded shape, reaching only about 20 feet tall with a spread of 15 feet.
5. Zelkova serrata
Japanese zelkova (Zelkova serrata) is a member of Ulmaceae, but is happily resistant to Dutch elm disease, making it a welcome substitute for the beleaguered elm. It’s tolerant of unforgiving urban conditions, so it’s often used as a street tree but does well in a wide range of situations.
Mature height tends to reach 80 feet and spreads are 50 to 75 feet, forming a vase-shaped crown (several cultivars are bred to be much smaller). Although full sun is preferred, partial shade is also suitable for zelkova. Soil preference tends to lean toward the acidic, although zelkova can tolerate well-drained, slightly alkaline soil. It is hardy in zones 5 to 8.
In spring, small, light green, rather insignificant flowers emerge along with the foliage. The flowers develop into plain, wingless drupes that ripen in the fall. Three-inchlong, medium green leaves feature ciliate marginal teeth; foliage remains clean through the season until color change in autumn. Depending on cultural conditions and cultivar, fall color can range from a subtle yellow to rich shades of yellow-orange and red-brown.
Smooth, gray bark is yet another ornamental attraction: It tends to exfoliate with maturity to reveal a cinnamony, orange-brown inner bark.
Zelkova generally suffers few insect or disease problems.
Cultivars have been bred to feature shorter stature, as well as rounder or narrower crowns.
- City Sprite® (Zelkova serrata ‘JFS-KW1’) features an oval to vase-shaped habit, reaching only 24 feet tall with an 18-foot spread. Fall color is a brilliant, glowing golden yellow.
- Z. serrata ‘Green Vase’ features a narrower vase shape than the species, and is faster growing, too. Foliage is a bit darker green in summer and turns a rich mix of orange, bronze and red in autumn.
- Z. serrata ‘Village Green’ grows to about 60 feet with a 50-foot spread, maintaining a resolute vase-shaped crown. Reddish fall color distinguishes it from other yellow varieties.