Two for summer
Crested gentian (G. septemfida, zone 3)
Small, trumpet-shaped, medium blue flowers clustered at the ends of 20-centimetre-tall stems characterize the crested gentian. Its narrow, spoon-shaped leaves are both dark green and evergreen (if protected by snow). Also commonly known as everyman's gentian, it's tolerant of a range of soils and sites, making it easy enough for a novice to grow yet lovely enough for the seasoned alpine collector. Each plant expands to form a circle about 30 centimetres across with stems splayed out from a central crown and turned up at the ends to show off their flowers. For an attractive, natural-looking display, plant this gentian in groups of three, 20 centimetres apart, among large rocks close to a pathway where the intricacy of blooms can be appreciated against a neutral background.
Willow gentian (G. asclepiadea, zone 5)
Coming from a family of shorties, the willow gentian (its name derived from its long, narrow leaves resembling those of a willow) is something of an oddball, growing from 60 to 100 centimetres tall. This species is normally found growing near streams, so for impressive growth and flowering, try to replicate the dampness of its natural home by planting in rich, moist soil, fattened up with a large helping of peat or leaf mould. Mulch with a thin layer of decayed leaves or compost to hold moisture and maintain a cool root zone. Situate where it will receive some shade during the hottest part of the day. Its blue trumpet-shaped flowers, with darker blue inside, appear in ascending clusters at the top of arching stems, starting in July and continuing into August.
Two for fall
G. x macaulayi, zone 4
Standing all of 10 centimetres tall, this autumn-flowering gentian trails stems of narrow, dark green leaves along the ground before turning upward in September to show its trumpet-shaped flowers with flaring mouths, often five centimetres wide. Its colour is a clean medium blue with white streaks and violet undertones along the throat. Some of the prostrate stems may root as they travel, and bits can be snipped away and replanted in full sun or dappled shade in moist, slightly acidic soil. ‘Kingfisher' has slightly larger flowers of a brighter blue.
G. sino-ornata, zone 6
Resembling G. acaulis in form and markings, this Nepalese species is vivid blue and opens in September and October. Growing all of 10 centimetres high, the clumps of narrow, grasslike leaves must be protected from the hot, midday sun and kept evenly moist through the summer. Filtered shade from trees that do not suck up every drop of moisture is ideal. Satisfy the plant's preference for slightly acidic soil by mixing in well-rotted leaves, peat moss or compost, and (as with the others) pick a place among rocks away from big, floppy perennials that could soon smother smaller gentians. If a clump grows large and looks divisible, slice into it with a knife and trowel out a segment for immediate replanting (or temporary potting) in early May or just as new growth begins to show.