Hemerocallis

A tough, clump-forming herbaceous perennial whose common name comes from its bloom habit — each flower opens for a single day, but a well-budded scape opens fresh blooms in succession over weeks. Modern garden daylilies are overwhelmingly hybrids, with more than 60,000 cultivars registered, in nearly every color but true blue. Full-size classics like 'Hyperion' carry fragrant, 4-inch flowers on naked scapes rising to about 3 feet above arching, blade-like foliage; the plants tolerate rabbits, erosion, and urban conditions and ask very little once established.

A tough, vigorous clump-forming perennial — the classic orange "tawny daylily" or "ditch lily" seen naturalized along roadsides and old homesteads. Each rusty-orange, trumpet-shaped flower opens for a single day, but tall branched scapes (to 3-6 feet) open fresh blooms in succession through early-to-midsummer above arching, strap-like foliage. Native to eastern Asia, not North America; the commonly grown form is a sterile triploid that sets no seed but spreads aggressively by thick rhizomes, forming dense colonies. Famously bulletproof and adaptable, but plant it knowing it will run.