Fern-leaf yarrow

An airy, see-through ornamental in the vervain family (Verbenaceae), native to South America and naturalized across the warm southeastern United States. NC State Extension describes an erect plant 2 to 5 feet tall on thin but strong red-marked green stems, topped from summer into fall by dense, flat-topped clusters of small tubular purple-lavender flowers held well above mostly basal, lance-shaped, serrated dark-green leaves. A perennial in USDA zones 7-11 (grown as an annual in colder climates), it is fast-growing, drought and deer tolerant, and a magnet for bees, butterflies, and hummingbirds - though it self-sows freely and some sources have labeled it invasive.

Creeping cotoneaster is a deciduous spreading shrub native to the mountains of central and southwestern China, Nepal, and Taiwan, prized for its distinctive flat herringbone branching, tiny pink-white summer flowers, and masses of vivid red autumn berries that sustain birds through winter. It holds the RHS Award of Garden Merit and tolerates poor, dry soils on banks and walls where little else will perform. The honest catch is twofold: the berries are mildly toxic to humans and pets (cyanogenic seeds, GI-irritant flesh), and the plant self-seeds freely enough that it is naturalising widely in the UK and Ireland and is considered potentially invasive - a real concern before planting near wild margins or hedgerows.

Arkansas blue star (Amsonia hubrichtii), also called threadleaf bluestar or Hubricht's bluestar, is a clump-forming native perennial from a tiny wild range in the Ouachita Mountains of Arkansas and Oklahoma that has become one of the most dependable foliage perennials in temperate gardens. It builds a soft, rounded, knee-to-waist-high mound of upright stems clothed in very fine, needle-like, thread-thin leaves, so the whole plant reads as a feathery green cloud through summer. In late spring the stem tips carry loose clusters of small, pale powder-blue, five-pointed star flowers, a quiet but pretty show that draws butterflies and other pollinators. Its headline act comes in autumn, when the fine foliage turns a clear golden-amber that lights up the border and earned it the Perennial Plant Association Plant of the Year for 2011. It wants full sun to part shade and is famously tough, adaptable, and deer-resistant, though it will flop open in too much shade or overly rich soil, so give it sun and a light shearing after bloom if you want it to stay upright.

The original black-eyed Susan - a bristly-stemmed, short-lived meadow daisy that behaves as an annual, biennial, or brief perennial depending on where it grows. It blooms hard and early from seed, then carries itself forward by reseeding rather than by spreading into a permanent clump.

A long-lived native perennial of central and eastern US woodland borders and prairie meadows with deep blue pea-shaped flowers in late spring, blue-green leguminous foliage, attractive black seed pods for winter interest, and a nitrogen-fixing root system (Fabaceae). Larval host for 6 documented butterfly species per NC State (orange sulphur, clouded sulphur, frosted elfin, eastern tailed-blue, hoary edge, wild indigo duskywing) - among the highest Lep-host-count perennials in the eastern flora.

An architectural, branching perennial grown for the metallic steel-blue flush it takes on in summer: small, egg-shaped flowerheads, each ringed by a collar of spiny, silvery-blue bracts, are held on rigid, blue-tinted stems above a basal rosette of leathery, heart-shaped leaves. It is a tough, genuinely drought-tolerant plant for hot, dry, sharply drained, even poor sandy or gravelly soil in full sun - it resents rich, wet ground, where it rots and flops - which makes it ideal for gravel gardens and coastal, seaside plantings, and one of the best long-lasting cut and dried flowers. At the height of summer it is a magnet for bees, butterflies, and hoverflies. It is grown purely as an ornamental and is not eaten.