Common blue violet

A clump-forming aromatic native perennial of eastern North America, grown as much for its silvery floral bracts as its bloom - the upper leaves below each flower head turn a frosted, dusty-mint color in summer. Dense flat-topped clusters of tiny two-lipped pinkish-white flowers cover the plant from mid to late summer and are a magnet for bees and butterflies. Unlike the true mints (Mentha), it spreads only modestly by rhizome and is not invasive.

A clump-forming native milkweed with bright orange summer flowers, strong pollinator value, and tolerance for dry sunny sites.

Lanceleaf coreopsis is the yellow daisy most gardeners picture when they hear coreopsis, and the fact worth leading with is lifespan. The Lady Bird Johnson Wildflower Center calls it the commonest coreopsis and easy to grow, drought tolerant, and not reliably perennial - a phrase that carries far more weight than a plant tag ever gives it. What you buy flowers hard for two or three years and then thins from the middle out. What keeps the planting going is seed: Missouri Botanical Garden records that it self-seeds freely and will naturalize into large colonies, and rates maintenance MEDIUM rather than low precisely because managing that seed is the recurring job. Everything else about it is easy. It wants dry to medium, well-drained soil in full sun, does best on poor sandy or rocky ground, and Missouri Botanical Garden records it as tolerant of heat, humidity and drought. Flowers are solitary yellow daisies 1 to 2 inches across, eight rays toothed at the tips over a flat yellow disc, from May into July, carried on slender stems above narrow hairy lance-shaped leaves that sit mostly in a basal tuft. Two decisions follow from the seeding. In a meadow, a rock garden, a prairie planting or a dry bank, let it seed and treat the stand as self-renewing rather than as individual plants. In a border, deadhead through the season and divide every two or three years, or accept that you are growing something that moves around. And know what it does where it does not belong: it is listed as an Invasive Alien Species in Japan, where the same freedom with seed has made it a serious pest.

A low North American native prairie perennial whose nodding, reddish-pink to purplish globular flowers in spring are upstaged by what follows: as the seeds form, the styles elongate into upright, feathery gray plumes that collectively read like wisps of smoke - the source of its many regional names (prairie smoke, old man's whiskers, long-plumed purple avens). A soft, hairy plant to about 16 inches with fern-like, pinnately divided leaves; it spreads slowly by rhizomes into a low groundcover and prefers cool-summer climates and dry, well-drained soil.

The first thing to settle about plains coreopsis is the thing seed racks are vaguest about: it is an ANNUAL. Missouri Botanical Garden types it that way without hedging, the Lady Bird Johnson Wildflower Center calls it an annual in its first line, and the plant germinates, flowers, sets seed and dies inside one season. That single fact separates it from the other two coreopsis in this group. Lanceleaf coreopsis and largeflower coreopsis are true perennials that gardeners routinely expect to be long-lived and that are not quite: MBG says lanceleaf needs dividing every two or three years in a border to stay robust; threadleaf coreopsis, already in this catalogue, is the one that genuinely persists. Plains coreopsis persists differently - not as a plant but as a seed bank. It self-sows heavily, and a stand that looks permanent after five years is five generations, not one plant, which is why it is the coreopsis for a meadow sowing and the wrong one for a slot in a border where something has to be there next April. What you get for accepting that is the best flower in the genus for the money. Solitary daisies one to two inches across, seven to nine bright yellow rays each painted maroon at the base around a red-brown disc, carried in quantity on wiry branching stems above finely cut foliage. MBG rates it showy and good for cutting, lists no serious insect or disease problems, and puts its maintenance at low. It is the plant behind most of the yellow in a roadside wildflower mix. Two cautions belong next to that. It self-seeds hard enough that MBG recommends deadheading specifically to prevent it, and it has naturalised across nearly fifty territories outside its home range, from Britain and Poland to Japan, Java and Fiji - so treat spare seed as something to bin rather than scatter. And the two best sources disagree about water: MBG grows it dry to medium and calls it drought tolerant, while the Wildflower Center rates its water use HIGH and says the good years are the wet ones. Both are describing the same plant honestly, and the record below explains why.

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.