WSU Clark County Extension

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Scientific name: Dahlia cvs.

Type:Bulbs, corms, tubers, rhizomes
Plant Requirements
Zone:7 to 10
Plant Characteristics
Height:4 ft
Width:2 ft
Bloom:Summer flowers
Bloom Time:July to September
Bloom Color:Orange
Additional Characteristics



Wildlife value

Description Garden Dahlias are widely grown for their large zinnia-like flowers that come in multitude of shapes and colors (white, violet, yellow, orange, pink, red, dark-red) during the late summer and early fall.

Dahlias are classified as herbaceous perennials which arise from tuberous roots. While there are many different cultivars the commonly grown types typically attain a size of 4’ with a width of 2’. Dahlias are organized into ten (10) different classifications or flower groups: Single, anemone, collarette, waterlily, decorative, fall, pompon, cactus, semi-cactus and miscellaneous.

The leaves are classified as pinnately compound. Leaflets are ovately shaped with toothed margins.

Best flowering occurs in full sun, but plants generally appreciate some lightly filtered shade in hot summer climates. Site in locations sheltered from strong winds. Taller varieties usually need staking which should be put in place next to the roots at the time of planting.

Plant tubers outside in the spring 1-2 weeks before the last frost date. After foliage dies down the tubers are dug up and stored dry over the winter. Northwest growers in the milder regions often find they don't need to dig up the tubers in the winter.

Potential diseases include viruses, crown gall, root rot, wilts and powdery mildew.
For assistance, contact Dr. Charles Brun (, (360) 397-6060 5701
Computing and Web Resources, PO Box 6234, Washington State University, Pullman WA 99164-6234