Spiny bear's breeches

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.

A bold, moisture-loving native perennial of eastern North America that dies back to a woody base each winter and returns to throw up stout 2-6 ft stems topped with enormous 4-8 inch saucer-shaped flowers - white, pink, red, or burgundy, each with a contrasting central eye - from June into September. NC State Extension describes a herbaceous perennial hardy across USDA zones 4a-9b that thrives in wet to constantly moist soils, tolerates heat, humidity, and even brief flooding, and draws hummingbirds, butterflies, and other pollinators. The tropical-looking dinner-plate blooms make it a dramatic focal point for rain gardens, pond edges, and the back of a sunny border.

A tough, EVERGREEN, rhizomatous iris relative from South Africa - native to the Cape Provinces and KwaZulu-Natal along the summer-rainfall eastern seaboard (POWO, Kew) - grown for fans of stiff, sword-shaped leaves and white, iris-like flowers marked with yellow and violet. Each flower lasts only a single day, but they are borne in repeated flushes over weeks, which earns the plant its nickname, the "fortnight lily." Unlike the dormant Cape bulbs it is grown alongside, this is an EVERGREEN rhizome with NO dormant season - a drought-tolerant, low-maintenance landscape workhorse for full sun or light shade that, once established, asks almost nothing and tolerates a wide range of soils. It is the HARDIEST of this Cape group (to about USDA zone 8b; the RHS rates it borderline-hardy, about H4) and is a reliable, low-care evergreen for warm-temperate and Mediterranean gardens. The wiry flower stems re-bloom, so leave them in place; tidy only the old leaves. It is bee- and insect-pollinated rather than bird-pollinated, and it is not a food plant.

Bear's breeches is a bold Mediterranean perennial whose dramatically lobed, glossy leaves inspired the Corinthian column capital of classical architecture. Its wild native range spans the central and eastern Mediterranean - Italy, Sicily, Sardinia, the Balkans, Greece, the Aegean, Anatolia and the Levant, plus NW Africa (Morocco, Algeria, Tunisia); it is naturalised (not native) further west into Iberia. In gardens it serves as an architectural statement plant, producing tall white-and-purple flower spikes in summer on established clumps. The honest catch is its root system: fleshy, deep-running tuberous roots regenerate readily from the smallest fragment, making Acanthus mollis genuinely difficult to eradicate once established and a declared invasive in Australia and New Zealand, so site selection is a permanent decision.

The stately, classic tall border perennial - the parent of the great Elatum-hybrid delphiniums - grown for towering, densely packed spires of spurred flowers, most famously an intense pure blue (also purple, white, or pink), each bloom centred on a contrasting tuft of petals known as the "bee." It rises on tall hollow stems above deeply palmate-lobed leaves and flowers in early to mid summer. Magnificent but high-maintenance and load-bearing in its honesty: the tall spikes need staking and shelter from wind, the plant is hungry, thirsty, fairly short-lived, a slug magnet on its emerging shoots, and it dislikes hot, humid summers, performing best in cool-summer climates. It is also HIGHLY TOXIC in all parts (diterpenoid alkaloids), and the sap can irritate skin - which is also what makes it reliably deer-resistant. POWO (Kew) places it native to the mountains of Europe across to Siberia and central Asia; RHS rates the species fully hardy (H7) and has given the Award of Garden Merit to many of its hybrids.

A bold, tropical-looking rhizomatous perennial grown for its big, paddle-shaped banana-like leaves and slim spikes of red, orange, or yellow flowers from summer to frost. Native to Central America, South America, and the West Indies, Canna indica is the wild ancestor behind many garden canna hybrids - narrower-flowered and more upright than the showy modern cultivars, with hard, round black seeds once used as shot, which give it its common name. It thrives in heat, humidity, and consistently moist to wet rich soil in full sun, where it forms erect clumps that read as instant tropical structure. In its hardiness range (zones 8a-11b) it overwinters in the ground; colder gardeners lift and store the rhizomes.