Dahlias: August's flower

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From now until frost, dahlias are the garden’s glamour girls, flaunting their ruffled skirts and flashing their look-at-me colors in a seductive, nonstop show.

It would be hard to name another flower with such prolific bloom and diversity of form. There are daisy-like types and fat, multi-petalled kinds that resemble roses; spiky, cactus-flowered varieties and perfectly symmetrical pom-poms; waterlily types and anemone varieties. That’s just the flower forms.

The palette is enormous (everything but blue), including solids, blends and petals with contrasting streaks and tips. The names are flamboyant: ‘Boogie Woogie,’ ‘Sonic Boom,’ ‘Crazy Legs,’ ‘Candy Eyes, ‘Pink Giraffe,’ ‘Lucky Ducky.’ And the size range is wide, from 13-inch dwarfs to 6-foot monsters.

Today there are more than 57,000 registered dahlia cultivars with more in development all the time. The diversity is partly what brings out the collector’s itch and the competitive grower’s ambition. But there’s really no explaining the devotion that keeps dahlia fans talking about their knobby tubers, fussing over their plants and even propping umbrellas over potential show flowers to keep colors from fading.

Dahlias were once a serious crop in the MidAtlantic, especially on Long Island, where they were grown for New York City markets. Then the Depression hit, and farmers couldn’t sell them.

You could make a fair living selling flowers before the crash; at a time when average salaries ran to $25 a week, flower sales (dahlias, gladiolus) at 50 cents per dozen could generate $50 to $100 a day. But once the bottom fell out of the market, many growers plowed their flowers under to grow vegetables.

Chrysanthemums have largely replaced dahlia in the marketplace, but dahlias are still a favorite with home gardeners for their long period of bloom, saturated colors and huge variety. They make excellent cut flowers, too. One of the larger mail order suppliers in our area, Longfield Gardens, is based in Lakewood, N.J. (contact info below).

Ruth Hartnup/Flickr

While dahlias are extremely reliable, they do require a bit more work than many other plants. They are native to Central and South America, and understanding them includes knowing that they are strictly fair-weather friends that won’t tolerate frigid winter temperatures.

Dahlias are grown from tubers (fleshy roots that look like sweet potatoes) that must be planted after temperatures warm and dug up after first frost. Even with the best kind of storage, some tubers will wither and die. This isn’t really off-putting to dahlia-smitten individuals like Andy Vernon, author of “A Plant Lover’s Guide to Dahlias” (Timber Press, $25).

“My advice is not to get overly hung up on the non-hardy nature of dahlias,” Vernon writes. “New plants are relatively inexpensive and quick to grow, so look at a rotten old tuber not as a loss, but as an opportunity to grow something new.”

Many growers start tubers indoors to get some size on the plants before they go outside. Slugs and snails find the tender new shoots irresistible, so planting straight into the ground can make it hard to get plants going without serious counter-measures. Try non-toxic, iron phosphate  baits like Sluggo.)

Once up and growing, the plants are hungry and thirsty. Ample amounts of cow manure and high-test fertilizer (5-10-10 is good), copious amounts of water and vigilance regarding bugs are the keys to success.

Bloom season runs from mid-summer to frost, peaking in late August and September, when dahlia shows are scheduled. The first kiss of frost blackens the plants and calls for garden forks to harvest tubers for winter storage. Then it’s a matter of checking the tubers now and then, trading or auctioning off some and plotting greater glories next season.

In the language of the flowers, dahlias are thought to represent elegance, commitment and discovery. Well, that works. Discover this reliable flower, commit to its care while acknowledging its limits and elegance will be yours.

Plant sources:

Longfield Gardens, 1245 Airport Road, Lakewood, NJ 08701. Call 855-534-2733 or see longfield-gardens.com.

Pleasant Valley Glads & Dahlias, Box 213, West Suffield, CT 06093. Call 860-798-8189 or go to gladiola.com.

Swan Island Dahlias, 995 NW 22nd Ave., Canby, OR 97013. Call 800-410-6540 or visit dahlias.com.