Sedum

A tiny, mat-forming evergreen succulent with crowded, fleshy, yellow-green leaves that disappears under bright yellow, star-shaped flowers in early summer. It is a ground cover for hot, dry, poor and rocky soil, rock gardens, wall tops and the edges of paths, hardy in USDA zones 4 to 9. It also spreads beyond the garden: the Flora of North America records it naturalized across the northern United States and southern Canada, NC State Extension calls it weedy and aggressive, and the RHS says it may be invasive, so plant it only where its spread is welcome. The leaves taste sharp and peppery, and the sap can irritate skin.

Orpine is a clump-forming, upright herbaceous succulent perennial with stout stems clothed in fleshy, toothed, grey-green leaves. In late summer and autumn the stems are topped by broad, flat heads of small star-shaped dusky-pink to red-purple flowers that age to rich russet and stand through winter. It is the wild parent behind the famous border sedum 'Herbstfreude' / 'Autumn Joy', and one of the best late-season pollinator plants for the garden - the broad flowerheads swarm with bees and butterflies when little else is in bloom. Drought-tolerant and happiest in poor, sharp-drained soil in full sun.