Bloom county: Dahlias are a vibrant local tradition

They’re a local tradition.

In fact, Snohomish County and Washington have officially proclaimed 2009 the Year of the Dahlia in honor of the Snohomish County Dahlia Society’s 100th birthday.

This year the society will host its 100th show of blossoms in conjunction with the American Dahlia Society’s National Show, coming to Everett in August.

This might be year to take up dahlias.

It’s not too late to plant them now for stunning summer flowers.

Ideal planting times for dahlias are from late April to mid-May in Western Washington.

Local clubs are hosting tuber sales this month, including the Snohomish County Dahlia Society with sales April 19, 25 and 26.

Tubers, which look a bit like potatoes, grow into plants up to 6 feet tall in a single season, depending on the variety.

Much like tomatoes, they produce their crop steadily from late July until frost kills them.

“This is probably one of the best locations in the world to grow dahlias,” said Hills Collins of Marysville, a member of the Snohomish County Dahlia Society. “They’re very easy to grow.”

Dahlias love Western Washington’s relatively long growing season and temperate summers.

Their blooms range from dainty and daisylike at 2 inches across to giant globes that could fill a 12-inch dinner plate.

Gardeners hoping for a bounty of cut flowers, however, should choose varieties with moderately sized flowers. Big bloomers tend to droop sooner and don’t produce as many flowers per plant, said Collins, who grows about 500 dahlia plants a year.

Dick Ambrose of Camano Island, who has been growing dahlias since the early 1970s, said varieties with blooms 6 inches across and smaller can produce about eight times as many flowers as the gargantuan cultivars.

Ambrose first started growing dahlias after attending the local society’s show.

“I was amazed,” Ambrose said. “I walked in there and they just knocked my socks off.”

Over the years Ambrose and his wife, Susan, have introduced more than 100 dahlia hybrids of their own, including about 70 officially recognized by the American Dahlia Society.

They’ve named many of their introductions after their home island, including Camano Sitka, a cactus-style variety that will be offered at the society’s tuber sales.

Dahlias at the local society’s sale will be $3 each, a steal for plants not typically sold at big box stores, Collins said.

“Most of the members grow them to show them,” Collins said. “You’re getting good varieties at these club sales, no matter what club.”

Sarah Jackson: 425-339-3037, sjackson@heraldnet.com.

Dahlia tips

Timing: Plant tubers when the soil warms up, usually in late April or mid-May after local clubs have their annual tuber sales. Dahlia tubers are susceptible to rotting if the soil is too wet. They can also freeze if a late frost hits the new shoots.

Location: Plant dahlias in full sun with at least six hours of direct sunlight. Afternoon sun is better than morning sun. Plant taller varieties at the back of mixed borders. Use shorter varieties for front borders or low hedges.

Soil preparation: Thoroughly turn the soil at least a week before planting. Provide good drainage by adding compost, well-rotted manure, leaf mold or peat moss. Planting in heavy clay soils can lead to rot.

Planting: Place a stake in the ground and dig a hole 4 to 6 inches deep on each side of the stake with stakes about 2 feet apart. Place the tuber flat with the eye looking up and cover loosely with soil. Any dahlia plant taller than 2 feet should be staked and tied.

Fertilizing: 1 tablespoon of a time-release fertilizer such as Osmocote can be sprinkled in the planting hole.

Watering: Dahlias like deep watering more than frequent light watering. During summer heat, water every four to five days.

Cutting: Cutting encourages more growth. Cut early in the morning or late at night, slightly before flowers are all the way open.

Pest control: Slugs love dahlias in the spring. Surround young plants with slug bait. Aphids and earwigs can also be pests.

Digging: Many dahlia varieties are hardy enough to stay in the ground all winter. Benefits to digging and storing dahlias, however, include easy propagation through division and protection from winter rot or frost. If you do leave them in the ground, divide them every third year for nicer, bigger flowers and stronger stems.

Source: Snohomish County Dahlia Society