How to grow for show: 10 tips for prize-winning dahlias

Published 1:30 am Monday, July 14, 2025

You know it’s showtime when umbrellas are shading dahlias in the garden.

Umbrellas protect the American tuberous-rooted plants so their blooms don’t fade in the hot sun or get damaged by heavy rain.

Dahlias love the region’s climate and gardeners love them back.

The Snohomish County Dahlia Society is among the American Dahlia Society’s 70 chapters in the United States and Canada. Many have yearly contests with at least 100 prizes.

Summer is a great time to get serious for the show. Snohomish County Dahlia Society’s Alysia Obina and Doug Symonds, club president and vice president, offer these 10 tips and tricks for growing blue-ribbon blossoms.

They’re all so beautiful,” said Symonds, a retired data technician and society member for 34 years. “Dahlias have every color, form and size you can think of. Except for blue – there are no blue dahlias.”

(The 1946 film “The Blue Dahlia” is pure Hollywood.)

JOIN THE CLUB

Snohomish County Dahlia Society meetings are held at 7 p.m. on the second Thursday of the month at Legion Hall, 145 Alverson Blvd., Everett. Zoom links to attend virtually are also available.

Each meeting includes a seasonal program on plant culture, refreshments and a door-prize drawing. Many top Northwest Dahlia growers attend these meetings and are more than happy to share their know-how.

“Don’t be afraid to ask questions,” said Obina, a financial counselor. “People in the club want to pass along their knowledge. We’ll teach you everything you need to know.”

And be sure to visit local dahlia shows and farms to discover varieties you would like to add to your collection.

TAKE CLASSES

The Snohomish County chapter offers a range of classes. Do take a judging class, even if you don’t want to be a judge, as it will help you understand how to grow near-perfect flowers.

Judges evaluate the color, form, substance, bloom position, foliage and stem. The county show has three divisions — novice, amateur and open. Contestants compete for 135 awards. A perfect score is 100 points.

PLANT TONS

Grow lots of dahlias. The more you plant, the more likely you’ll grow a top-scoring flower.

Symonds grows about 1,000 plants on his half-acre dahlia farm at his mother-in-law’s home in Marysville, whereas Obina grows 300 plants in eight garden beds and 60 pots in her Lake Stevens backyard.

“I stuff as many as I can in my tiny backyard,” she said. “As soon as I can get rid of that jacuzzi back there, I will have room for even more.”

COLLECT TUBERS

You can grow up to 100 plants from just one tuber or seed head. Cuttings also work.

Fellow hobbyists can help. Many of the flowers Obina and Symonds grow are originated by local hybridizers who cross-pollinate their plants to create a new variety.

In 2018, Obina won Best Medium Single with the bright red and yellow flame cactus dahlia “AC Abby” at the North Central Washington Dahlia Society show in Wenatchee. Her mentor introduced the flower.

“My mentor gives me a lot,” said Obina, who joined the county chapter in 2012. “It’s another reason to join the club – for free tubers.”

DISBUD AND DISBRANCH

If you grow dahlias to show, you can’t just plant the seeds or tubers and let them grow on their own. Do that and you’ll get a mess of blooms, some short, others tall, none perfect.

Instead, disbud and disbranch your plants to achieve a more perfect bloom.

“For the giant dahlias, we grow four flowers per plant,” Symonds said. “We remove everything else.”

TEST YOUR SOIL

A soil test will tell you exactly how to supplement your garden to grow dahlias.

Symonds recommends kits from local soil-testing company MySoil. You can buy a test kit for $32 at mysoiltesting.com.

Whether your soil is sand or clay, alkaline or acidic, dahlias do well with the help of organic material such as leaf mold, compost or manure.

CONTROL PESTS

Locally, slugs, earwigs and aphids are blights for blooms.

If you see these pests in your garden, remove them by hand, wash them off the plants with soapy water and bring in beneficial bugs to eat the bad ones. As a last resort, selectively spray an insecticide.

Or break out the booze.

“We like to get the slugs drunk,” Obina said. “We put bowls of beer out and that gets a lot of them.”

INVEST IN IRRIGATION

To water their dahlias, Obina uses soaker hoses and Symonds uses drip tape. Overhead sprinklers aren’t recommended because they could tear or leave spots on the petals.

Drip irrigation is recommended because it gets water to the roots. Soaking garden beds two or three times a week should be enough during the summer, but do it every day if temperatures hit 80 degrees or higher.

STAY GROUNDED

Club members take dahlias very seriously, but it’s important to stay grounded.

“Have fun,” Obina said. “Sometimes people are a little too serious about it and they forget about the fun in it. It’s a flower – it’s just a flower.”

And don’t forget the umbrellas. Symonds uses 100 of the beach-sized variety to protect 1,000 dahlias.

“We actually have had people go along the street and they say, ‘I love the umbrellas! They are so fun to look at!’” he said.

GET INSPIRED

The Snohomish County Dahlia Society’s 116th annual show is 1-6 p.m. Aug. 16 and 10 a.m. to 4 p.m. Aug. 17 at Floral Hall in Forest Park, 802 E. Mukilteo Blvd., Everett. Admission is free.

The two-day event, co-sponsored by the Everett Parks Department, features colorful displays of up to 2,000 blooms.

For more: scdahlias.org, email: scdahliasociety@gmail.com or call 425-923-7945.

Contact writer Sara Bruestle at slbruestle@gmail.com.