Clematis

A long-lived, twining summer perennial, clematis flowers mostly
in blues, purples, pinks, and whites.

FLOWERING CLEMATIS is the perfect complement to trellis and lattice walls. It climbs by the stems of its leaves; these short petioles need twiggy, vertical support to get started.

A long-lived, twining summer perennial, clematis flowers mostly in blues, purples, pinks, and whites, with a few yellows. As a group, the flowers bloom from early May through frost, but an individual's season usually lasts a month or two. Forms vary, from hand-size starfish to inch-wide four-point stars to bell-like blooms, with a counterpoint of showy flower parts in the middle for texture. The small, compound leaves mature into a thick mass, providing neutral cover, quite dense in some varieties.

No one, perhaps, knows their endless variations better than Susan Austin, proprietor of Completely Clematis, the Ipswich, Massachusetts, nursery devoted to the genus. For openers, Austin recommends early, tough, pale-pink Clematis alpina 'Willy' (Zone 6), which has nodding, up to 1-1/2-inch blooms in May and June. Compact, it matures to six to eight feet in length and needs no regular pruning. Just remove all flowering shoots immediately after bloom is past. It doesn't tolerate poor drainage or otherwise boggy conditions. Pink varieties of early C. montana, such as 'Elizabeth', 'Pink Perfection', and 'Tetrarose', are of similar culture but larger and with more-fragrant blooms.

For the second act, she suggests the July and August bloomer C. viticella 'Etoile Violette'. Medium-size, it grows 6 to 12 feet. The purple-blue fadeproof, velvety three-inch stars are marked with creamy stamens -- a muted drama.

And of course, there's the showstopper sweet autumn clematis, C. terniflora -- a runaway September bride in a veil of honey-sweet ivory stars. Every expert I spoke with praised it as the ultimate, easy-to-grow, goes-with-everything vine. The crisp, vaguely mottled foliage and wiry golden seed heads add interest before and after the 3/4-inch dotted-Swiss flowers appear.

Sweet autumn will cover a trellis or a chain-link fence with equal abandon, even colonizing sloping or gravelly areas ravaged by new construction. Just prepare a gallon-size pocket of good soil, supply water (until the third year) as needed, and stand back. A single mature plant can spread 20 to 30 feet, and though the vines are wiry and light, it can grow into a substantial thicket, quite woody at the base. It also thrives along tough city streets, wherever there's soil between asphalt and concrete. It is hardy to Zone 4.