Bird of paradise

A near-indestructible architectural houseplant grown for stiff, upright, sword-shaped, succulent leaves banded in grey-green - yellow-margined in the popular "Laurentii" - and long known as the snake plant or "mother-in-law's tongue". POWO records it as native to tropical West Africa, and its currently accepted botanical name is Dracaena trifasciata (it was reclassified out of Sansevieria), though the nursery trade and most gardeners still know it as Sansevieria. It is famously tough: it tolerates low light, deep shade to bright indirect light, neglect, and irregular watering, which makes it one of the most forgiving plants you can grow indoors. HONESTY: the commonest way to kill it is OVERwatering - soggy soil rots the rhizome - so the real skill is letting the mix dry out between waterings, not watering more. It is toxic to cats and dogs (saponins cause vomiting and diarrhoea if eaten), and the popular "releases oxygen at night and purifies the air" reputation is overstated at realistic room densities. RHS treats it as a tender houseplant (H1B), frost-tender and grown under glass or indoors except in frost-free climates.

David viburnum is a compact, mound-forming evergreen shrub native to western China (its provenance usually given as the Sichuan / Yunnan region), grown for its bold, deeply three-veined glossy leaves, small clusters of white flowers in late spring, and - when fruiting - striking oval drupes in a distinctive metallic turquoise-blue. It holds the RHS Award of Garden Merit and suits the front of borders, shaded corners, and containers in cool-temperate to mild climates. The honest catch is a fundamental one: it is dioecious, so you must plant at least one male and one female together to get the celebrated blue fruit - a single plant in isolation will never berry, and many gardeners discover this only after years of waiting.

Japanese box is a compact, dense evergreen shrub long cultivated in Japan (where it was first described from cultivated plants of uncertain wild origin) with truly wild populations known from Taiwan, used for centuries for topiary, low hedging, and bonsai. Its fine-textured small leaves and naturally tidy habit make it one of the most widely planted formal garden shrubs in temperate regions, and the 'Faulkner' cultivar holds the RHS Award of Garden Merit. The honest catch is a double threat: all parts contain steroidal alkaloids (cyclobuxine) and are toxic to humans and livestock, and the species is under sustained pressure from box blight (Calonectria pseudonaviculata) and the box tree moth (Cydalima perspectalis), with B. microphylla documented as more susceptible than the common European B. sempervirens, so an established hedge can be defoliated within weeks.

Snowrose is a small evergreen-to-semi-evergreen shrub native to open subtropical woodlands and wet meadows from India through southern China to Japan (Wikipedia), prized for its near-continuous flush of tiny white funnel-shaped flowers, opening from pink buds, from early spring to near autumn. It thrives in containers and is one of the world's most commonly sold bonsai subjects, tolerating hard pruning and offering dense, fine-textured foliage. The honest catch is twofold: it is frost-tender (USDA zones 9-11 outdoors; zones 7-8 only as a protected container plant), and it is notoriously fussy - overwatering, underwatering, cold drafts, or simply being moved can trigger sudden, dramatic leaf drop. (Note: GBIF now files this taxon under the accepted name Buchozia japonica, with Serissa japonica a synonym.)

A rosette-forming evergreen succulent native to the grasslands, desert scrub, and pinyon-juniper woodlands of Arizona, New Mexico, Texas, and northern Mexico at 4,000 to 8,000 feet. Thick, rigid blue-gray leaves with toothed margins and a one-inch terminal spine form a dense, symmetrical basal rosette to about 24 inches tall by 3 feet wide. Surprisingly cold-hardy for a succulent - reliably hardy to USDA Zone 7 and reported to survive -20°F as long as the cold is dry rather than wet. Each rosette flowers only once, after 10-30 years, sending up a single 20-foot stalk before dying and leaving its rooted offsets behind.

A giant herbaceous perennial from Southeast Asia and the principal wild ancestor of most cultivated dessert bananas. What looks like a trunk is a 'pseudostem' - tightly rolled leaf sheaths - topped by a fountain of huge, paddle-shaped leaves that can run 6 to 10 feet long, giving an instant tropical effect. In frost-free climates (USDA zones 10a-11b) an established clump produces a drooping flower spike and a hanging bunch of edible fruit, then that pseudostem dies and is replaced by a sucker from the base. It is frost-tender: everywhere colder it is grown as a bold container or greenhouse foliage plant that is overwintered indoors and rarely, if ever, fruits.