Dahlia

Dahlia spp.

Asteraceae · perennial · introduced

Last updated May 19, 2026

Quick Facts

Height

1-6 ft (varies widely by type: border dahlias 12-18 in; dinner plates 4-6 ft)

Spread

1-3 ft

Growth Rate

Fast

Light

Full Sun

Soil

Well Drained

Water

Moderate

Hardiness

Zones 8–11 (in ground); 3-7 (with tuber lifting)

Bloom Time

July-October (peak September-October in PNW)

Origin

Mexico and Central America

Spring Emergence / Primary Infection

Dormant in Soil

View full calendar (7 stages)

Stage	Typical Window	What to Look For
Tuber planting BBCH 01	May 1-Jun 1	Plant tubers after last frost; soil 60°F+
Shoot emergence BBCH 09	May 20-Jun 20	Green shoots visible above soil from tuber eyes
Vegetative growth BBCH 31	Jun 15-Jul 15	Active stem growth; pinching point (when 4 sets of leaves)
First bloom BBCH 61	Jul 15-Aug 15	First flower buds opening
Peak bloom BBCH 65	Sep 1-Oct 15	Plants in full flower production; best quality blooms
Frost kill / tuber lifting BBCH 97	Oct 15-Nov 15	Foliage blackened by first hard frost; lift tubers within 1-2 weeks
Winter storage BBCH 00	Nov 1-Apr 30	Tubers stored in cool (40-50°F), dark, humid conditions

Data Maturity

Baseline Extension data. Expert review underway.