Perennial candytuft

Aubrieta (Aubrieta deltoidea) is a low, mat-forming evergreen perennial in the mustard family (Brassicaceae), native to the rocky hillsides of southeastern Europe - primarily Greece, the Aegean Islands, Crete, and adjacent Mediterranean coasts. It is one of the most reliable spring-flowering ground covers for sunny, well-drained spots: cascading sheets of violet to deep pink four-petalled blooms from March through May, attractive to bees and bee flies. The honest catch is that without a hard cut-back immediately after flowering, plants become woody and bare in the centre within two or three years, collapsing from a tight carpet into a tired, gappy mat.

Felicia amelloides is an evergreen, woody-based perennial subshrub native to a narrow coastal strip of South Africa's Western and Eastern Cape, where it colonises stabilising sand dunes, sandy flats, and rocky outcrops at 0 to 3,280.8 feet. In the garden it delivers a near-continuous flush of sky-blue, yellow-centred daisy flowers on neat mounding growth, typically 12 to 24 inches but capable of reaching about 3.3 feet, making it one of the few true blue-flowered plants for sunny pots and borders. The honest catch is frost-tenderness: it survives only light frost in sharply drained soil and collapses below about 23°F, so outside USDA zones 9-11 it must be overwintered under glass or replaced annually - a real commitment in cool-temperate gardens.

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

Campanula carpatica is a low, mounding herbaceous perennial native to the rocky subalpine habitats of the Carpathian Mountains, ranging across Poland, the Czech Republic, Slovakia, Romania, and Ukraine (Wikipedia). Its wide, upward-facing bell flowers in violet-blue, white, or pink appear from June through August, making it one of the longest-blooming edging perennials available, and it holds an RHS Award of Garden Merit. The honest catch is longevity: it tends to behave as a short-lived perennial, often thinning or declining after a few seasons, so gardeners should plan for regular division or fresh plants from seed to hold the planting.

A low, clump-forming native woodland violet of eastern North America, grown for its early spring blue-to-purple flowers with conspicuous white throats held over glossy, heart-shaped leaves. It does not run, but self-seeds freely - to the point of being weedy in rich, moist ground. A larval host for fritillary butterflies and a nectar source for early bees and butterflies; the leaves are high in vitamins A and C.

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.