Roses are synonymous with Portland, but there’s a different summer flower whose local fanbase is growing by leaps and bounds. What it lacks in scent it makes up for with a shockingly diverse array of shapes and colors, not to mention being far friendlier than the thorny rose. We’re talking about the dahlia.

You’ll find these bold blooms growing in gardens across the city, being sold by the bucketload at farmers markets, and adorning wedding arrangements. There are more than 20,000 different cultivars divided into whimsical categories like waterlily, cactus, pompom, and anemone — and they come in every color except blue and jet black. Fun fact: Because they grow from edible tubers, dahlias were originally classified as vegetables.

The 56th annual American Dahlia Society National Show, considered “the Olympics of dahlia-dom,” returns to Portland this week for the third time in its long history. The prestigious event draws commercial growers, hobbyists, and general enthusiasts from across the country. Visitors can expect to see judged exhibits and attend seminars covering topics like growing dahlias and new industry research.

The show takes place Thursday, Aug. 24-Monday, Aug. 28, at the Holiday Inn Portland Columbia Riverfront Hotel and Convention Center. It’s free and open to the general public Saturday, Aug. 26, and Sunday, Aug. 27.

Can’t get enough of these showy flowers? Swan Island Dahlias — the largest dahlia-growing business in the US since the 1960s — is holding its Annual Dahlia Festival now through September. Admission is free.