Gentiana acaulis is a low, mat-forming alpine perennial native to the mountains of central and southern Europe — the Alps, Pyrenees, and Balkans — where it grows in short turf and rocky meadows from 800 to 3,000 m elevation. In gardens it is prized for its astonishing, deep-blue trumpet flowers in late spring, and it has received the RHS Award of Garden Merit. The honest catch is its notorious habit of "sulking": well-established plants can refuse to flower for years with no apparent cause, and the gardener's only remedy is to dig and replant the mat a few inches away — a maddening behaviour that makes it a reliable showpiece in some gardens and a frustrating non-bloomer in others.

Farfugium japonicum is an evergreen rhizomatous perennial native to streamsides and rocky seashores of Japan, Korea, Taiwan, and coastal China, where it is known as tsuwabuki (石蘗). In gardens it delivers bold, kidney-shaped leaves up to 10 inches across and cheerful yellow daisy flowers in autumn and winter — a genuinely useful combination for dark, damp corners. The honest catch is toxicity: the plant contains petasitenine, a carcinogenic pyrrolizidine alkaloid; it must be kept out of reach of children and pets and handled with care, and it is frost-tender above USDA zone 7b, dying back or suffering severe leaf scorch in hard freezes.

Hakonechloa macra is a slow-growing, clump-forming deciduous grass endemic to Japan, naturally found on rocky woodland slopes near Mount Hakone and across Honshu. It is prized in shaded gardens for its gracefully cascading, fountain-like mounds of thin, arching leaves and warm autumn tones of red and pink. The honest catch is pace and site sensitivity: it is among the slowest ornamental grasses to establish, struggles badly in hot dry summers without consistent moisture, and is prone to leaf scorch if sited in too much sun — it needs rich, reliably moist soil to earn its reputation.

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.

Gerbera jamesonii, the Barberton daisy (also Transvaal daisy), is a tufted evergreen perennial herb in the daisy family (Asteraceae) native to the summer-rainfall grasslands and rocky woodland of north-eastern South Africa and Eswatini. It forms a basal rosette of lobed leaves from which leafless flowering scapes rise, each topped by a single large daisy-style flowerhead in orange-red, yellow, pink, or white. It is the wild ancestor of the thousands of florist gerbera cultivars and earns its place as a long-blooming focal point in borders and patio containers, attractive to bees and other insects. The load-bearing caution is frost-tenderness: RHS rates it H1C, meaning it survives outdoors only in summer or the very mildest, frost-free spots and must be overwintered under glass elsewhere (roughly USDA 9-11). It is non-toxic, with no reported poisoning hazard to people or pets, making it a safe choice where toxicity is a concern.

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 0-1,000 m. In the garden it delivers a near-continuous flush of sky-blue, yellow-centred daisy flowers on neat mounding growth, typically 12-24 inches but capable of reaching about 1 m, 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 23F (-5C), so outside USDA zones 9-11 it must be overwintered under glass or replaced annually — a real commitment in cool-temperate gardens.