When to Plant Dahlias in Arizona

Dahlias (Dahlia spp.) are the undisputed stars of the late-summer and fall garden, producing an extraordinary range of flower forms — from compact pompons to dinner plate-sized blooms spanning 12 inches — in virtually every color except true blue. Blooming from midsummer until the first hard frost, a single tuber grows into a massive, flower-laden plant that can produce dozens of cut flowers per week. Modern breeding has expanded the palette and forms dramatically; the American Dahlia Society recognizes over 20 flower forms. Extremely rewarding for gardeners willing to invest in the planting, staking, and (in cold zones) annual lifting of tubers.

Arizona spans USDA hardiness zones 10a, 6b, 7a, 8a, 8b, 9a, 9b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Dahlias planting dates based on your local frost dates.

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Dahlias Planting Calendar for Arizona

▸ Zone 10a ~364 day growing season · Full guide →

Last frost: January 1 · First frost: December 31 · 364 day season

Activity	When	Date Range
Transplant Outdoors	January 1	Jan 1 – Jan 15
Direct Sow	January 1	Jan 1 – Jan 22
Bloom	March 12	Mar 12 – Oct 8

▸ Zone 6b ~205 day growing season · Full guide →

Last frost: April 3 · First frost: October 25 · 205 day season

Activity	When	Date Range
Start Indoors	March 6	Mar 6 – Mar 20
Transplant Outdoors	April 10	Apr 10 – Apr 24
Direct Sow	April 10	Apr 10 – May 1
Bloom	June 26	Jun 26 – Oct 16

▸ Zone 7a ~221 day growing season · Full guide →

Last frost: March 25 · First frost: November 1 · 221 day season

Activity	When	Date Range
Start Indoors	February 25	Feb 25 – Mar 11
Transplant Outdoors	April 1	Apr 1 – Apr 15
Direct Sow	April 1	Apr 1 – Apr 22
Bloom	June 10	Jun 10 – Oct 14

▸ Zone 8a ~255 day growing season · Full guide →

Last frost: March 8 · First frost: November 18 · 255 day season

Activity	When	Date Range
Start Indoors	February 15	Feb 15 – Mar 1
Transplant Outdoors	March 8	Mar 8 – Mar 22
Direct Sow	March 8	Mar 8 – Mar 29
Bloom	May 17	May 17 – Oct 18

▸ Zone 8b ~276 day growing season · Full guide →

Last frost: February 25 · First frost: November 28 · 276 day season

Activity	When	Date Range
Start Indoors	February 4	Feb 4 – Feb 18
Transplant Outdoors	February 25	Feb 25 – Mar 11
Direct Sow	February 25	Feb 25 – Mar 18
Bloom	May 6	May 6 – Oct 21

▸ Zone 9a ~303 day growing season · Full guide →

Last frost: February 10 · First frost: December 10 · 303 day season

Activity	When	Date Range
Transplant Outdoors	February 10	Feb 10 – Feb 24
Direct Sow	February 10	Feb 10 – Mar 3
Bloom	April 21	Apr 21 – Oct 20

▸ Zone 9b ~329 day growing season · Full guide →

Last frost: January 25 · First frost: December 20 · 329 day season

Activity	When	Date Range
Transplant Outdoors	January 25	Jan 25 – Feb 8
Direct Sow	January 25	Jan 25 – Feb 15
Bloom	April 5	Apr 5 – Oct 18

Growing Tips for Arizona

Plant tubers after all danger of frost has passed and soil temperature reaches 60°F — typically 1–2 weeks after last frost in most zones. Lay tubers horizontally 4–6 inches deep with the eye (growth point) facing up. Do not water until sprouts emerge; wet soil rots dormant tubers. Stake tall varieties (over 3 feet) at planting time to avoid root disturbance later. Pinch growing tips at 12–16 inches to encourage branching and more blooms. Deadhead regularly to extend the blooming season. In zones 8b and warmer, tubers can overwinter in the ground with a layer of mulch. In zones 3–8a, lift tubers after the first killing frost, cure for a week, and store in slightly damp vermiculite or peat at 40–50°F until spring. Divide tubers every year or two; each division must have an eye (bud) to grow.

Dahlias in Other States

Frequently Asked Questions

When should I plant Dahlias in Arizona?

Planting dates for Dahlias in Arizona depend on your USDA zone. Arizona spans zones 10a, 6b, 7a, 8a, 8b, 9a, 9b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Arizona for planting?

Arizona contains USDA hardiness zones 10a, 6b, 7a, 8a, 8b, 9a, 9b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

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