Look closely at a diamond-dusted daylily flower, and you'll be enraptured. If it's aromatic too, you'll fall in love with the genus, one that is mostly trouble-free.

Daylilies (Hemerocallis) are not true lilies. They're fleshy-rooted perennials that don't grow from bulbs as lilies do. Flowers last for just a day, hence the name. As long as you meet some minimum requirements, they're as tough as old boots. They survive spray from salted winter roads, being uprooted and not immediately replanted, being chewed on by deer, and exposure to drought.

They need a well-drained soil, preferably rich with organic matter, fertilizer topdressing when spring growth is emerging, mulching with three or four inches of material to protect in winter, and dividing every three to five years.

For most varieties, the more sun exposure the better. Only a few tolerate some shade. All require plentiful water when first planted and through their first year, but are tolerant of some drought after they're established. They can be planted at any time the ground is not frozen hard. They're good at holding soil on a slope, too.

A few varieties will withstand shade, but generally there'll be fewer blossoms in shady conditions. Some folks plant them under maple trees, giving them extra water to compensate for the thirst of tree roots. Some daylilies that grow in a half-day of shade may have clearer colors - especially those with red or purple blossoms - than the same cultivars grown in full sun.

There are 30,000 to 40,000 different varieties of Hemerocallis on the market, and so many professional and amateur hybridizers at work that there's an almost constant replacement of varieties. If you want an old variety, you'd better find someone who's growing it and bargain for a root.

Hemerocallis includes about 15 species, and they include nocturnal flower opening or diurnal; single, double or spider (narrow-petaled) flowers; ruffled or smooth flowers; evergreen or dormant plants; aromatic or non-aromatic; diploid, triploid and tetraploid chromosomes; miniatures or standards; rebloomers; those with "diamond dusted" flowers; blossoms in nearly every color except blue; and early, mid-season, and late-blooming.

Dormant varieties are recommended for Northern gardeners, evergreen varieties for the hottest areas of the country. Chromosome numbers are mainly important to breeders. The old Hemerocallis fulva, the orange "ditch" daylily, is a sterile triploid, propagating from roots and often seen as a relic of an abandoned farmstead.

Deadheading, or removing flowers just below the bump (ovary) prevents seed. If you want to grow daylilies from seed, be advised that it will take about three years before they bloom in our climate. Seed-grown daylilies often are disappointing.

When blooming is no longer profuse, your daylilies may need to be divided. Dig up the whole clump, hose off soil, then separate roots by teasing them, putting spading forks back-to-back in the clump and prying, or using a sharp meat cleaver or axe to cut the roots apart. Discard damaged roots; these are vulnerable to rot and disease.

When your daylily has finished blooming and the scapes (stalks) begin to brown, look at the stalks for proliferations, or tiny new daylilies forming on the scapes. These clones may be harvested (cut an inch above and an inch below the proliferation) and treated as green cuttings. They should be protected from freezing, etc., until spring, then planted out.

Daylily buds and flowers are edible. Some savor them with sorbets or fruity sherbets, others steam or saute them.

Margaret Lauterbach: melauter@earthlink.net or write to Gardening, The Idaho Statesman, P.O. Box 40, Boise, ID 83707.