It's December and time for my annual list of top-performing plants, the ones I feel will make fitting additions to your exterior design this spring.
These appeal to me, not just because they're hardy, long-lived and resistant to diseases and insects, but also because they're rare, hard-to-find, ornamental collectibles.
* Disanthus (Disanthus cercidifolius). Michael Dirr, a woody-plant guru, author and University of Georgia professor, describes this plant as "a magnificent but rare plant worthy of the discriminating gardener's attention." I first saw disanthus at Brookside Gardens in Wheaton. This member of the witchhazel family turns a dazzling orange-maroon and holds its colorful foliage well into October. The large rounded leaves of this 8-to-12-foot-tall shrub prefer dappled shade or a northern exposure, lots of compost, good drainage and protection from drying winds.
* Fragrant snowbell (Styrax obassia). This woody plant grows to 20 feet in height. Prune the lower branches as it gets larger, and turn it from a shrub into a small tree. Then, when it's in bloom, you can stand under the 8-to-10-inch-long, arching racemes of fragrant white flowers. It tolerates shade but is best planted on the fringe of woods, where it will be protected by the trees and still get sun. The more light this deciduous Asian native gets, the more sweet-smelling blooms it will produce. Plant near the patio as a tree or to the back border as a shrub. Its 4-to-6-inch rounded leaves present a coarse texture and sometimes color yellow in the fall.
* Persian parrotia (Parrotia persica). The leaves open reddish-purple in spring, and the trunk displays a lacy-textured, exfoliating bark. A small deciduous tree with an upright habit, it grows to 30 feet in as many years. The foliage displays beautiful yellow-orange to scarlet colors every autumn. To ensure success, even though this plant tolerates drought and poor soil, plant in a well-drained site with plenty of compost.
* Shantung maple (Acer truncatum). At 20 to 25 feet in both height and width, this is one of the best small maples for patio or town house gardens. The low, rounded growth habit also makes it a good candidate for a mixed shrub border. It prefers well-drained soil rich in organic material but is tough enough for most conditions. Shantung is drought-tolerant and resists late-summer margin browning, or leaf scorch. The tree is also called purpleblow maple for its beautiful reddish-purple glow when leaves bud in the spring. Leaves are deep green and glossy all summer and an outstanding orange-yellow in the fall.
* Stewartia (Stewartia species). It should take only a few calls to garden centers to find a version of this, my all-time favorite flowering tree--unless you want a particular variety. Garden centers seldom have more than one variety, but all are winners. Planted in moist, well-drained acidic soil, they're problem-free and 25 feet tall in maturity, with four seasons of interest, exfoliating bark, yellow to orange-red fall color and white, camellia-like flowers in the summer.
Among the different types, tall stewartia (S. monadelpha) has a gorgeous russet-red bark; Korean (S. koreana) has a more pyramidal habit; Japanese (S. pseudocamellia) develops a handsome, multi-hued tan bark. And mountain stewartia (S. ovata), native to the Southeastern United States, is smaller, 15 feet, and can be grown as a small tree or large shrub.
* English or common primrose (Primula vulgaris). Here's a situation where common is good. Primroses return for years as spring-flowering perennials, but this is often the only one still standing after several years, when numerous showy hybrids have disappeared. It's evergreen, so there is foliage in winter, and the yellow flowers are a joy to behold in late winter to early spring.
Some hybrids have been developed from this hardy species. You might not find common primrose, since it's used mostly for breeding. If you can't find it, look for a hybrid named Wanda, pink to red flowers, with a very long blooming period. These prefer partial shade and deep organic rich, moist soil. With enough moisture they tolerate full sun and will grow to cover the area. They never need to be divided. Plant them along moist areas and on the edge of woods.
* Flying saucers tickseed (Coreopsis grandiflora "Flying Saucers"). You will find many varieties of coreopsis, some very different from others. All are long-blooming perennials in full sun. Flying saucers is a patented variety with large flowers (one to 1 1/2 inches). Despite this plant's 15-inch size, its blossoms and dense foliage make quite a show as an edging, in masses mixed with other perennial groupings or on its own. The bright-yellow blooms continue to cover the plant from early summer into fall. Pruning the spent flowers encourages more blooming. Once established, they are drought-tolerant.
* Hakone grass (Hakonechloa macra "Aureola"). There are no showier, better-performing grasses for shady sites than hakone. This grass, which grows 18 inches in height and spread, has performed well in only three hours of sunlight. The leaves grow with an arching habit to about 18 inches and form graceful masses. The yellow variegation on the blades makes it look as if the sun is shining on it, even in shade. It will brighten a woodland floor or sunny spot if planted in moist, well-drained soil, high in organic material.
* Heath spotted orchid (Dactylorhiza maculata). Something appeals to me about being able to grow orchids in your own back yard. This one is a terrestrial orchid--it grows in the earth and gets nutrients from the soil. Exceptionally hardy, it sports purple-spotted foliage and pink to red flowers from mid-spring to late summer. Flowers occur in dense, upright clusters above lance-shaped leaves. The tallest of these deciduous orchids grows to 24 inches in height and returns yearly, especially in moist, acidic soil high in organic material. Plant along stream banks, in a woodland garden or in a partially shaded mixed perennial border by the patio. Your guests will notice the flower but never guess it's an orchid.
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is email@example.com