Gentians are all about blue-clear, intense, eye-catching blue. If their small floral trumpets were magenta, lavender or yellow, the flower might otherwise go unnoticed; but only a very distracted gardener could fail to spot and admire the brilliant blues of gentians.
The genus Gentiana is vast, with roughly 350 species scattered around the globe in mountain meadows, pastures and bogs, and beside streams. But despite their plentitude, only a few are worth growing: some are dull or nondescript; others are fussy about site. One of the prettiest gentians grows wild in our geographic backyard. Along the shores of Ontario's Lake Huron, sky-blue fringed gentians (G. crinita syn. Gentianopsis crinita, Zone 3) root down in mossy hollows and narrow fissures in the limestone slabs that edge the water. Experts agree that the fringed gentian is a difficult species to cultivate—best for it to stay windblown and wild. Still, there are enough other varieties to tempt any gardener. As a rule, gentians prefer a woodland soil: moist but well drained and supplied with a generous amount of humus in the form of crumbly leaf mould or compost. Choose a site that catches the sun for at least half the day or offers dappled shade, but avoid hot spots seared by the full force of afternoon rays.
Two for spring
Trumpet gentian (G. acaulis, zone 3)
Every spring, sometime in early May, I get down on my hands and knees and count the pointed green buds rising from a ground-hugging, dark green mat of trumpet gentians (also known as the stemless gentian; acaulis translates as "no-neck") tucked against a boulder in our rock garden. One year there may be two or three flowers above tiny, pointed leaves, the next year a dozen skyward-facing trumpets may appear. The intensely blue blooms are set off by green stripes on the exterior and a white throat spotted with blue. As with many alpines, this native European mountaineer displays disproportionately large flowers (six centimetres long) for the plant's otherwise small scale. Beautiful and not very common in gardens, our trumpet gentian is a plant we treasure and fret over, even though it has survived for 10 years and come through at least two divisions and transplants.
Spring gentian (G. verna, zone 4)
A wee mite, just five centimetres tall and wide, the spring gentian grows small rosettes of oval-shaped, dark green leaves in May, all but covered with a host of star-shaped, deep blue flowers with white throats—if you're lucky, that is. This little one has a reputation for being sulky and short-lived. But it's still worth a trial in a rock garden pocket of lean soil that's gritty with small stone chips rather than stuffed with organic matter.