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How to Get Late-Summer Color in Your Garden

A strategic mix of annuals and perennials yields a brilliant garden when the heat is really on

High-Impact, Low-Cost Summer Garden

Photo by Jerry Pavia

By August, most perennial gardens look more than a little weary. You can tidy up a bit by clipping off spent flowers, but sorry-looking foliage may be all that's left. Yet even on the hottest days of late summer, a garden can be ablaze with color, as Kay Burdick's Idaho garden proves.

Shown here as they look in late August, the undulating beds are packed with combinations that work even in tiny yards. To get her glistening show of golds, reds, and oranges accented by whites and purples, Kay grows a well-planned mix of perennials and annuals—especially marigolds, whose seeds she saves and replants year after year, costing her nothing. Keep reading to see how you can do the same.

Shown: Marigolds, asters, zinnias, and greenish-white dusty miller put on a robust late-summer show.

Unique Beauty from Familiar Plants

Photo by Jerry Pavia

Like many gardeners, Kay started out modestly, with just a few small beds, and expanded gradually. Today, her flower borders look so stunning that people often pull off the road to stare when they are driving past her house, which sits on a rise in the northern Idaho town of Bonners Ferry and has a sweeping view of the Selkirk Mountains.

The trick to having a lot of late-season color, Kay says, is to think in terms of waves of blooms. She has her spring flowers, including swaths of bulbs, such as tulips, daffodils, and hyacinths. Then come the early- to mid-summer bloomers, including irises, peonies, and poppies. The final flourish begins with the late-summer bloomers you see here, including dahlias, black-eyed Susans, coreopsis, and zinnias, alongside all those marigolds. As summer transitions into fall, asters and chrysanthemums join in the chorus.

Shown: Billowy, fragrant Russian sage and russet-colored Japanese barberry create sprawling clouds of color.

Sun-Loving Borders

Photo by Jerry Pavia

"In early summer, we'd cut back the spring flowers, after they were spent. That was harvest number one. Then when the irises and poppies faded, we'd have another harvest for the compost pile." A final cleanup in late fall got the yard tidy for winter.

These days Kay keeps up the stunning flower show on her own, thanks to time-saving tricks that reduce tedious chores such as weeding, watering, and deadheading. To minimize weeds, she makes sure plants cover all the tilled soil, since exposure to sunlight is what triggers many weed seeds to sprout. She plants her late-summer flowers in the springtime, tucking transplants in among the spring bulbs while they are still blooming. To ensure that each transplant will grow into a mound that touches its neighbors in all directions, she plants densely, often in zigzag rows.

Shown: Reds, oranges, and yellows mix with hot pinks and purples in this showy late-summer garden.

Tried and True Summer Garden Tips

Photo by Jerry Pavia

Kay's planting strategy requires lots of transplants—hundreds of them—so she grows her own from seed. She has a 14-by-20-foot greenhouse now but got by with windowsills for 20 years. She suggests that beginner gardeners start by buying nursery flats of annual seedlings and asking longtime gardeners if they have any perennial plants to share. Kay has had people knock on her door with that question, and she's happy to oblige, since many perennials do better when they are thinned periodically anyway.

Because she plants so densely, Kay doesn't have to worry about spreading compost throughout the season to keep the soil covered. She does it once a year, in late fall or early spring, depending on the weather. She maintains two big compost piles so that she can harvest from one and add to the other each year. She alternates layers of her clippings with manure from her horses and vegetable scraps from her kitchen, and uses a garden tractor to mix the ingredients several times each season.

Shown: A fountain hewn from a rugged boulder adds the cooling sound of flowing water.

Easy-Care Summer Garden Tips

Photo by Jerry Pavia

Watering's never a problem for Kay because she has an in-ground irrigation system. Soaker hoses or drip tubing linked to a timer are a simpler, less expensive option.

And cutting back spent flowers and foliage? Kay minimizes that chore by not being obsessive. She says she never tidies up the marigolds by deadheading. Since she wants the seeds, fading marigolds aren't a problem in her eyes; they are an investment in the future.

Shown: In pots and baskets, tuberose begonias brighten low-light areas well into fall with colorful flowers and intriguing leaves.

Kay's Standout Annuals

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She does need to cut back spent plants periodically, of course, but she's found that if she does a little each evening, usually less than an hour, her yard never gets out of control. "When I go home at night, that's what I do to relax," says Kay, who now runs the family collision-repair business on her own during the day. "I go out and smell the flowers. It's a lot more fun than fighting with insurance companies."

Here are the annuals that pump out new blooms until frost without plants becoming ungainly or too leggy.

Dahlia (Dahlia pinnata)

Available in many colors, this sturdy, small-headed annual is easily grown from seed. It doesn't require the stout staking and overwintering of dug-up tubers that larger garden dahlias require. Grows 6 to 18 inches tall. Full sun.

Interactive TOH Plant Hardiness Zone Map

Marigold (Tagetes)

Photo by Frank Krahmer/Getty Images

Annual marigolds come in two main types: "African" (T. erecta), which grow to 4 feet, and "French" (T. patula), which stay under 18 inches. Despite the common names, both originated in Mexico and Central America. They thrive in hot locations. Full sun.

Interactive TOH Plant Hardiness Zone Map

Zinnia (Z. elegans)

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Also originally from Mexico, this annual comes in many forms and colors: white, pink, salmon, yellow, purple, and even lime. Flowers range from less than

1 inch to nearly 7 inches across. Grows 8 to 36 inches tall, depending on variety. Full sun.

Interactive TOH Plant Hardiness Zone Map

Colorful Summer-to-Fall Perennials

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And, if you don't have the time to grow and plant annuals every year, put in these perennial bloomers for some vibrant, late-season color.

Obedient Plant (Physostegia virginiana)

Native to central and southern states. Produces pink or purple flower spikes that resemble snapdragons. Common name refers to the way individual flowers stay (temporarily) in whatever position they're pushed. Hardy to −40 degrees F. Full sun.

Interactive TOH Plant Hardiness Zone Map

Joe Pye Weed (Eutrochium purpureum)

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An eastern native. Flowers form in pink nosegays atop leafy wands 5 to 7 feet tall. Hardy everywhere. Full sun but light shade in hottest areas.

Interactive TOH Plant Hardiness Zone Map

Cardinal Flower (Lobelia cardinalis)

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Native mostly to boggy areas of North America. Lights up moist garden beds with spikes of inch-long, vivid red flowers. Hardy everywhere. Full sun or partial shade.

Interactive TOH Plant Hardiness Zone Map

Blazing Star (Liatris spicata)

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Native to eastern and central states. Produces spikes up to 4 feet tall topped by white, lavender, or pink flowers. Hardy almost everywhere. Full sun.

Interactive TOH Plant Hardiness Zone Map

Japanese Anemone (A. x hybrida, A. hupehensis japonica)

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Sends up willowy stems with pink or white flowers in fall. Can spread to cover large areas unless soil is dug around it to disturb roots. Hardy to −20 degrees F, with a thick mulch. Partial shade.

Interactive TOH Plant Hardiness Zone Map