Barking Up the Right Tree
One of my favorite spots in my garden is a small grove of river birch (Betula nigra). Imagine a stunning and lustrous white bark that peels to expose light reddish-brown to cinnamon underlayers. As the tree matures, the trunk usually becomes a dark reddish-brown, deeply lined and broken into oddly shaped platelike scales. There are many possibilities among individual trees because there is a lot of variability in this species. Some people claim the color is everything from salmon pink to fabulous shades of brown. Frankly, each tree is exciting and the differences make it a unique planting. River birch grows medium to fast, which makes it a good choice for new homeowners, usually averaging 40 feet tall. The small dark green leaves provide light shade, making river birches the perfect foil for perennial or ground cover plantings beneath their branches. 'Heritage' does better in hot climates. It grows to optimum size in moist soil, but survives in drier soils. Hardy in USDA Zones 4 to 9.
Crape myrtle (Lagerstroemia indica) is a fast-growing small shrub or tree that lends southern gardens added charm. Their long flowering season (in mid to late summer or early fall) and the variety of flower color gives this plant a wow factor. Many of them have great fall color. They are listed hardy in USDA Zones 7 to 10, but some are hardy in a sheltered location in Zone 6, and some gardeners grow them as perennials beyond the northern fringes of their hardiness zone. Their roots are much hardier than their tops; I have one that died to the ground, but came up the following years from the roots, just shorter. Crape myrtle concentrates its foliage near the top of its trunks, leaving its beautiful bark for all to enjoy at any time of year. Depending on the cultivar, the bark can be smooth gray, tan or even whitish; exfoliating combinations of browns and gray also occur.
American hophornbeam or ironwood (Ostrya virginiana) is a small- to mid-sized native with a rounded profile and drooping branches, topping out at 25 to 40 feet. Its nickname, musclewood, comes from the sinewy ridges of its trunk; the grayish-brown bark is broken into slender longitudinal strips. Another attractive feature on this tree is the reddish-brown, zigzag twigs. It flourishes in full sun to partial shade in dry and rocky soils. USDA Zones 3b to 9.
Japanese zelkova (Zelkova serrata) is a marvelously tall, vase-shaped tree that reaches 50 to 80 feet in height. This fast-growing tree is considered the replacement for the American elm. It has distinctive foliage, lovely ascending branches and interesting textured bark. In the young tree the bark is a handsome cherry-like, brownish-red, but as it ages it peels to show gray, green, orange and brown. A great shade tree, the zelkova is very wind- and drought-tolerant once established, and it resists pollution and tolerates a wide range of soil pH. Hardy in USDA Zones 5 to 8.
Beginning in youth (the second year or so), the cinnamon and reddish bark of paperbark maple (Acer griseum) begins to peel. In older trees, exfoliation may slow down or stop, but the bark retains its rich brown and red tones. In winter the snow accentuates the young reddish-brown stems. This slow-growing, small (20 to 30 feet) tree adapts to clay soils but prefers moist, well-drained soils in full sun. Its hardiness and performance and make this a great small specimen tree. Fits beautifully into smaller landscapes. Hardy in USDA Zones 5 to 8.
Typically 20 to 30 feet high and wide in the landscape, this venerable specimen of Kousa dogwood at Longwood Gardens in Pennsylvania, measures approximately 35 feet wide.
When we think of dogwoods we think of spring. Yet Kousa dogwood (Cornus kousa) is a plant with great seasonality. The flowers (actually, bracts) appear after the leaves open and persist for six weeks or longer. The Kousa dogwood has wonderful fall color and produces red fruit that looks like raspberries. The berries are edible, but the birds will devour them first. After the leaves and fruit and gone, one can truly appreciate the exfoliating bark that in maturity changes to wonderful mottled shades of gray, tan and vibrant brown. The bark, plus its strong horizontal branching, turns this small (20 to 30 feet) tree to a picturesque winter beauty in form and color. Hardy in USDA Zones 5 to 8.
Japanese Flowering Cherry
Blooming as early as April, the Japanese flowering cherry (Prunus serrulata) is often considered a spring sentinel. The single or double flowers range from white to deep pink; fragrance is an added bonus. 'Kwanson' exhibits a striking orange to bronze foliage color in fall. Once the foliage has fallen, this tree glows with its magnificent bark that dazzles the winter landscape. The bark exfoliates to reveal glossy patches in shades of red, brown and mahogany, and the corky horizontal lenticels are genuinely attractive on most cherries. Most people prefer cultivars that get only 20 to 25 feet tall, while the straight species gets to be 50 to 75 feet; considered to be a fast to medium grower. Hardy to USDA Zone 5.
The Japanese stewartia (Stewartia pseudocamellia) is one of the most handsome large trees for the landscape. This 30- to 40-foot tree is a real specimen. It flowers in July with 2- to 3-inch blooms that are white, vase-shaped and exquisitely fragrant. In fall its long, dark green leaves may turn a myriad of fall colors, from yellow, red to reddish-purple. And in winter, stripped of leaves and flowers, it shows off its sinewy bark that exfoliates in irregular plates of tan and brown. You may have to search a little for the Japanese stewartia at good nurseries, but the hunt is worth it. USDA Zones 5 to 8.
The dawn redwood (Metasequoia glyptostroboides) is a giant among its peers; this fast-growing deciduous conifer can reach heights of 70 to 100 feet and has been part of the global landscape for more than 50 million years. It has a neat cone-shaped habit and is very upright. The fine-textured foliage may turn orange-brown, red-brown or simply brown before dropping. The pendulous dark brown cones add appeal. In youth the bark is a stark reddish-brown, becoming darker and grayer with age, peeling and developing deep fissures. The dawn redwood's base becomes buttressed and develops uneven lengthwise ridges. It grows in full sun in moist, well-drained soils. Hardy in USDA Zones 5 to 8.
Some evergreens can hold their own when it comes to bark. The lacebark pine (Pinus bungeana) sports shiny, dark green, stiff needles. This 30- to 50-foot specimen pine appears rounded in youth, but as it matures it becomes open, flat topped and handsome. The dramatic bark exfoliates to a variety of colors ranging from olive green to brown, gray and white. This unique lacy pattern offers visual appeal all year-round. The cones are two to three inches long and add winter interest. Hardy in USDA Zones 4 to 8.
Junipers tend to be overused in the landscape and like some comedians they tend to get no respect. Yet Eastern redcedar (Juniperus virginiana), an American native, has significant landscape value as a hedge, windbreak or even a topiary. The better ornamental forms and colors of this are the 25 or more cultivars derived from this species. It's extremely hardy and can be grown in USDA Zones 2 to 9, where it can tower over the landscape at 40 to 50 feet tall. The needles are a deep green and, when brushed, waft the smell of a cedar chest. The tree produces lustrous brown cones, some giving the appearance of blue. Eastern redcedar is tolerant of many soil types in full sun, fairly easy to grow and is considered one of our toughest evergreen landscape plants. The bark is gray to reddish brown and peels in long strips. Look for cultivars such as 'Glauca' with silver blue foliage or 'Silver Spreader' with silvery-gray foliage if you want something different.
An interesting tree that was a specimen at a former home was the shagbark hickory (Carya ovata) which was a very large tree in a small backyard. It came with the house, and if you find one in your landscape, it's definitely worth keeping. This tree can be 60 to 80 feet tall but, given the right environment, might make 120 feet. It is adaptable to a wide range of soils, but prefers well-drained garden loam. The leaves turn yellow and golden-brown in fall. American natives loved this tree for its edible and easy-to-gather nuts. If you like them, you may have to wrestle a few squirrels to get some. The bark is a lovely gray and brown that exfoliates from either end but is attached in the middle. This makes the tree look old and shaggy, hence its common name. Hardy to USDA Zone 4.
—Stephanie Cohen is co-author of The Perennial Gardener's Design Primer, which was named one of the best books of 2005 by the Garden Writers of America. Ms. Cohen writes and lectures extensively across the U.S. and Canada.