Garden Guide '07: Native Plants for All Seasons
By Carla Burgess
People who advocate planting native wildflowers, shrubs and trees offer many reasons for including these species in the home landscape. Many native plants are highly adaptable to local growing conditions, so they often flourish in the garden with less fuss. Planting natives also helps preserve biological diversity in a region, especially where the plants' natural habitats are being destroyed. But perhaps the simplest argument for planting native species is that many of them are just plain beautiful. No gardener can resist the tug of a botanical workhorse with a pretty face, whether it comes from across the ocean or down the road.
One horticultural irony is that many native plant species, though they may be common in the fields, meadows and forests that surround us, have historically been hard to find at the store. Gathering plants from the wild is not only impractical—with successful transplanting often difficult to achieve—but it is also largely frowned upon. Some native plants have been brought to the brink of extinction due to over-harvesting and illegal poaching. Over the past two decades, reputable horticulturists have learned to successfully propagate native plants by collecting seeds and cuttings. As a result, many native plants have been introduced into the horticultural trade.
Horticulturists continue to find and propagate native species that may have commercial appeal. They sometimes find a unique strain of wild species—a genetic variant—with unusual color, shape or size. It may be propagated to create a new version, or variety. Two wild species may also cross-pollinate to create hybrid offspring, or plants may be intentionally crossed in the laboratory.
The plants discussed here are all native to North Carolina, with most of them also found throughout a broader geographic region, such as the Southeast. The emphasis is on species that are not as well known but are worthy plants that are underutilized in landscaping. Most of the plants profiled were selected for their provision of ornamental interest throughout the seasons and their suitability for a range of climates and landscape situations throughout the state. Though you can find some of them on the shelves of mainstream stores, with a little legwork you should be able to find most of them through mail-order suppliers or the many native plant nurseries cropping up.
Shrubs and Small Trees
The flowering dogwood (Cornus florida) remains one of the most common native flowering trees in home landscapes, and its status is well deserved. In the wild it thrives in the filtered sunlight beneath larger trees, but it grabs the limelight in sunny locations in the garden.
Lesser-used white-flowering native trees are equally capable of stealing the spring show and will invite fresh interest to your yard. Serviceberries (Amelanchier spp.) produce clusters of ornamental white blossoms in spring. The blooms are followed by edible, reddish-to-purple berries. Serviceberry is adaptable to a range of exposures and soil types, growing 6 to 25 feet, depending on species. Fringe tree (Chionanthus virginicus), sometimes known as old man's beard, has pompoms of straplike flower petals. A popular tree of generations past, it deserves a comeback. Plant it in sun to part shade in moist but well-drained soil.
Carolina silverbell (Halesia carolina) is laden with small (about 1 inch), white, bell-shaped blossoms that dangle from twigs in spring. Typically 20 to 30 feet tall, silverbells prefer rich, well-drained soil and light shade to full sun. A relative, Halesia diptera (two wing silverbell or snowdrop tree), is a bit showier; the variety 'Magniflora' has larger, more abundant flowers (about 1 1/2 inches).
Chalk maple (Acer leucoderme), a relative of the sugar maple, makes a wonderful shade tree for small spaces. It has spectacular autumn foliage in hues of yellow, orange or red. This deciduous tree ranges from 12 to 30 feet tall. It is usually multi-trunked, with smooth, pale-gray or whitish bark, and is suitable for sun or shade.
River birch (Betula nigra) has highly ornamental, peeling bark that may be white, brown, cinnamon or orange in color, which shows to best advantage in winter when its limbs are bare. It has multiple trunks and airy, graceful branches. In the wild, river birch may grow 40 to 70 feet. A dwarf variety, 'Little King', stays about 10 feet tall. 'Summer Cascade' has a lovely weeping form. Though it occurs naturally in moist environments, river birch adapts well to drier soil.
Red buckeye (Aesculus pavia) bears candelabras of red, spiky flowers in spring and tropical-looking foliage. It is typically 8 to 15 feet and has a mounding shape with a spread of about 8 feet. A disadvantage is that it drops its leaves early compared to other deciduous trees. Planting it close to another bushy, flowering shrub will divert attention. Though native to woodlands, it will flower best with more sun. Another stunning buckeye is the bottlebrush buckeye (Aesculus parviflora). It is a mounding shrub that sports upright 8- to 12-inch stalks of white flowers in midsummer. It makes a great specimen plant but can also be allowed to sucker and spread to form colonies or hedges. Locate it in partial shade to full sun. It is about 8 to 12 feet tall with an 8- to 10-foot spread. Fruits are 1- to 3-inch pear-shaped, tan capsules that split open to reveal glossy brown nuts inside (nuts are inedible). Leaves turn yellow or yellow-green in fall.
Needle palm (Rhapidophyllum hystrix) is a well-kept secret that needs to be spilled. Among the most cold-hardy of palms (to Zone 6), it avails even western North Carolina gardeners of a tropical look. Throughout the year, the plant sports fans of glossy, green leaves. It suckers to form a tidy clump, with a typical height of 5 to 6 feet and a spread of about 8 feet, though long-lived plants can become quite large. A record specimen in Texas is 28 feet tall and 13 feet around. A native of wet woodlands of the Southeast, needle palm is adaptable to filtered shade or full sun in moist or dry soils. Another similar-size hardy palm is the dwarf palmetto (Sabal minor). Site it in sparse shade to full sun. The trunkless palm has leaves a little wider, duller and more blue-green than the needle palm's. It produces clusters of erect white flowers in summer, followed by blue-black berries. With both palms, cold tolerance increases with age.
Oakleaf hydrangea (Hydrangea quercifolia) is truly a native for all seasons. Its midsummer flowers, held in cone-shaped panicles, open creamy, then fade to pink and tan. The leaves turn a rich burgundy in fall, and the exfoliating bark provides winter interest. Plant in sun to partial shade. It tolerates all but dry soils. It is typically 4 to 8 feet tall with a spread of 3 to 8 feet.
Coral honeysuckle (Lonicera sempervirens), sometimes called trumpet honeysuckle, is on the short list of North Carolina's most show-stopping native vines. Large clusters of 2-inch-long rich-red tubular flowers (yellow inside) cover the semi-evergreen foliage in spring. It is found in the shade of woodlands in the eastern half of the country. Give it sun and a trellis, mailbox or fence to climb and it will claim the space without swallowing your yard like the invasive Japanese honeysuckle. Coral honeysuckle is easy to discern from the non-native species by its leaves, which are opposite each other in pairs along the stem. It is irresistible to hummingbirds. Two other hummingbird favorites are crossvine (Bignonia capreolata) and trumpet creeper (Campsis radicans). These vines are engulfed in spring with orange blossoms. The vines are aggressive, so they are best suited to a natural area where they can climb trees or a substantial structure like the wall of a shed or barn. A large trellis in an area apart from cultivated beds and borders is also a good choice—especially where it would be practical to mow around it to control the many root suckers. Crossvine blooms earliest, with dark-orange and yellow flowers that are wider than trumpet creeper's and shorter, about 1 1/2 to 2 inches long. The dark green leaves are evergreen in warmer climates. Flowers of trumpet creeper are longer, 2 1/2 to 3 inches, with an orange exterior and rosy-orange interior. It blooms later and longer than crossvine, from early summer on. The foliage is made up of glossy, fernlike leaflets. The plant dies back in winter. Probably the most widely used native vine is Carolina jessamine (Gelsemium sempervirens), prized for its evergreen leaves and the sweet perfume of its yellow late-winter blossoms. The vines have a twining habit. The foliage takes on a bronzy-red tint in winter.
For those who appreciate a more delicate floral display, there's no topping the exquisite flowers of some of the native Clematis species. C. viorna has a bell-shaped, rosy-purple flower with a curled, cream-colored lip. C. virginiana, or virgin's bower, is sometimes confused with the non-native sweet autumn clematis. It has clusters of small, fragrant, white flowers in late summer, followed by highly ornamental feathery seedheads. It can be invasive, so keep it out of cultivated areas.
More rambling than viney, climbing aster (Aster carolinianus) can be either staked or left alone to ramble through perennial beds. This deciduous charmer is covered in fragrant, lavender-pink flowers from late summer through fall. An unusual native worth seeking out is Cocculus carolinus, known as Carolina coralbead or snail seed. With large, ivy-shaped leaves and round clusters of bright red berries in late summer, it's sure to keep your neighbors guessing.
If you have a smaller garden but still want to try some of the more vigorous vines mentioned here, try planting them in a sunken bucket to limit suckering and keep them trimmed back.
With hundreds of gorgeous perennial wildflowers to recommend, it's difficult to pick just a few. But baptisias (Baptisia spp.) sit at the back of the class raising their hands, begging to be called upon. With tall, luscious flower spikes (reminiscent of the harder-to-grow lupines) rising above blue-green pea-like foliage, this prairie native gets good grades all season. North Carolina has at least eight species of Baptisia, blossoming in hues of purple, white or yellow in late spring. Many wild variations have been cultivated for the nursery trade and hybridized as well. The most common baptisia on the market is B. australis, often called blue falso indigo, which has light-purple flowers and forms clumps of foliage 3 feet tall to 5 feet wide. B. alba is incredibly striking, with white flowers that contrast with smoky-colored stems. A coveted new variety is 'Purple Smoke', a variant discovered in Orange County that has the charcoal-colored stems of B. alba and flowers more violet than B. australis. Baptisias are sun-loving perennials that require a little patience as they mature to full advantage. Over the years, baptisias develop a deep taproot and form mature clumps. Baptisias flourish in average, well-drained soil and are drought-tolerant. The interesting, plump seed pods dry and darken in fall. The plant dies back to the ground in winter. New growth, resembling asparagus tips, emerges in spring.
Lobelia cardinalis, known as cardinal flower, revives the late summer garden with its tall, scarlet-red flower spikes. It likes moist soil in light shade to sun. Though it is short-lived, cardinal flower re-seeds prolifically. It looks equally good in drifts in a natural area or a formal border. The leaves form basal clumps (don't mulch heavily in winter or the crowns will rot). It is typically 3 to 4 feet tall. This exceedingly carefree flower is a hummingbird favorite.
Threadleaf coreopsis (Coreopsis verticillata) is a versatile perennial with fine-textured foliage that would be handsome even minus its small but profuse buttery-yellow flowers. About 12 to 24 inches in height, it thrives in average soil in full sun to light shade. The tops may be sheared lightly to encourage season-long blooms. The most commonly sold variety is 'Moonbeam'.
The low-growing green-and-gold (Chrysogonum virginianum) brightens up the semi-shady border or natural area with its star-shaped yellow flowers. Evergreen in some areas, it likes well-drained soil. About 6 inches tall, it is nice in rock gardens and makes an excellent groundcover for slopes. Foamflower (Tiarella cordifolia) is another woodland native, topped in spring with short, fuzzy, white flower spikes. Its heart-shaped leaves with prominent, dark veins are arranged in tidy clumps that are attractive all season. Many varieties are available, including some with light yellow-to-peach leaves. Foamflowers can tolerate full shade. They prefer moist, organic soil. They are 6 to 12 inches tall.
Purple coneflowers (Echinacea purpurea) are widely available in nurseries, and rightly so. There are dozens of varieties, but it's hard to beat the basic model. The rosy-pink, daisylike petals have bronzy-orange, cone-shaped centers. Coneflowers average 2 to 3 feet in height. Grow them in average-to-poor, well-drained soil in full sun. They are very drought-tolerant. Purple coneflowers are homegrown bird feeders. When the seed heads mature, the goldfinches come calling.
Just because a plant species is native to a region does not mean it will perform well anywhere in that area. The important thing to consider is the specific growing conditions in your landscape. Some species native to wet areas, for example, will want to have wet feet in your garden too. Others, though, are adaptable to a range of growing conditions beyond that of their natural habitat. Bald cypress, for example, is thought of as a swamp species, but this tree is equally happy in yards and even along urban streets. Also, keep in mind that the sizes given here are guidelines; height and spread may vary depending on where a plant is sited.
Native Plant Sources
Never dig plants from the wild. Sometimes, though, you may be able to "rescue" plants from a site slated for development. Always ask the landowner for permission and be respectful of the property. Make sure that any native plants you buy are nursery-propagated.
For links to suppliers of native plants in North Carolina, visit the North Carolina Native Plant Society's Web site at www.ncwildflower.org/natives/sources.htm.
For links to North Carolina suppliers and beyond, visit the N.C. Botanical Garden Web site at http://ncbg.unc.edu/plants-and-gardening.
"Growing and Propagating Showy Native Plants" by Richard E. Bir is an excellent guide to growing your own natives through seeds or cuttings. It is published by the University of North Carolina Press and is easy to find in public libraries.