Mum care calendar

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.

Thomas J. Story
Garden mums pictured at right (clockwise from top left) are 'Vanessa', 'Sweet Stacy', 'Bold Felicia', 'Donna', 'Cecilia', 'Helen', 'Stephanie', 'Olivia', and (center) 'Natasha'.

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.

Thomas J. Story
Yellow 'Donna' mingles with variegated sage and lemon thyme (top), while orange clumps of 'Olivia' line a dry creek bed (bottom) along with 'Aurea' Japanese barberry.

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.

Mum care calendar

SPRING, SUMMER

Water

Apply it often enough that the soil never dries out completely 1/2 inch below the surface.

Fertilize

In garden beds. When new growth emerges in spring, apply complete fertilizer (14-14-14 controlled-release fertilizer is a good choice). Feed again in late spring and again in mid-July. When the first flower buds show color, apply low-nitrogen plant food (like fish fertilizer).

In containers. If you're growing chrysanthemums as container plants, start with a dose of controlled-release fertilizer, then feed weekly with liquid fertilizer until buds show color.

Pinch

When new growth first reaches about 5 inches tall, pinch or shear off the top inch of foliage. Three weeks after first shearing, again cut off the top inch of new growth. For taller varieties, pinch back twice more, for a total of four times.

Pinching or shearing new growth forces the plant to branch where you cut it and to build up a strong undercarriage that supports heavier top growth later in the season. Plus, sheared plants produce more, smaller blooms, compared to unsheared ones, so make a greater impact in the garden.

LATE FALL

Cut back plants

Few plants respond better to the human touch than chrysanthemums. In late autumn after bloom, cut off chrysanthemums about 6 inches above the ground. This tidies them up for winter and makes it easier to spot new growth in spring. However, if you live in a climate with winters marked by regular hard freezes, you can improve your mums' winter survival by cutting off tops after new growth begins in spring.

If you're growing one of the new no-shear My Favorite series mums, cut back the plant only once, after fall bloom.