It's remarkable what centuries of plant breeding can do. Start with a simple yellow chrysanthemum and cross it with two or three other Asian species, and the result is florists' chrysanthemum (C. x morifolium), the spectacular late-season perennial that blooms in fiery tones. Its flowers ― which echo the russets, golds, and yellows of autumn leaves ― are especially loved by gardeners for their effective displays in the landscape, and for their associations with woodsmoke, frosty mornings, and the first days of the garden's quiet season.

Now, breeders are showing off new bicolors and colors new to certain types of mums. 'Mary-Jane', for example, is one of the first pink anemone-flowered mums bred for home gardens. And daisy-flowered mums have been introduced in colors that range from deep ruby red to amber.

If you aren't much of a hands-on gardener, no-shear My Favorite series mums, developed by researchers from the University of Minnesota, produce masses of small flowers over a long season. These compact plants need cutting back only once, after fall bloom. They include Autumn Red, Yellow Quill, Twilight Pink, White, and Coral.

Beautiful as they are, florists' mums are also versatile. You can mass them in big pots or in garden beds, or combine them with shrubs or perennials.

Are florists' mums just for florists?

Florists' chrysanthemums come in two types: garden mums, which are bred for the perennial border, and pot mums, which are bred for forcing as gift plants.

Unfortunately, most nursery labels don't tell you which are which. (There are hints, however: Yoder Brothers, the country's largest mum producer, gives garden mums women's names and gives pot mums the names of towns and cities.) The chart at right outlines the differences.

Garden mums take to the perennial border like a fish to water. Buy them in bloom, and plant them in full sun (light afternoon shade in hot climates). They like rich, well-drained soil and protection from dry, cold winter winds.

Pot mums, which are sold all year, ultimately take the same growing conditions. But since they must endure the stress of forced bloom and off-season transplanting, they need special handling to make the transition from hothouse to garden. Put them in a bright place indoors for no more than two weeks after you get them, watering as needed. Then move them to a protected place outdoors that gets filtered sun and no frost, for two weeks. Finally, cut the plants back by about two-thirds and transplant them into the garden.

If you live in a cold-winter climate and buy a pot mum in late summer or in fall or winter, cut it back after blooms have faded and keep it in a cool room or greenhouse until spring. Then transplant it into the garden.

Where to buy chrysanthemums

Since chrysanthemums are among the most widely sold perennials, they are easy to find in bloom almost anywhere this month. But if you want your pick of a broad range of flower and plant forms, try a specialist. Sunnyslope Gardens (8638 Huntington Dr., San Gabriel, CA; 626/287-4071) is a fine retail supplier that's been around for years. To order by mail, try King's Mums (209/759-3571). Though they ship only from March through June, they have an open house at their facility in Clements, California (near Lodi) in October and November.