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When to Plant Larkspur in Alaska

Larkspur (Consolida ajacis) is a cool-season annual that produces tall, delicate spires of blue, purple, pink, and white flowers reminiscent of its perennial cousin, delphinium. Direct-sown into cold soil or fall-sown in mild-winter climates, it blooms in spring before going to seed as summer heat arrives. An excellent cut flower and cottage-garden staple.

Alaska spans USDA hardiness zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a (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 Larkspur planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Larkspur Planting Calendar for Alaska

Zone 2a ~94 day growing season · Full guide →

Last frost: May 30 · First frost: September 1 · 94 day season

Activity When Date Range
Direct Sow April 18 Apr 18 – May 9
Bloom June 27 Jun 27 – Jul 25
Zone 2b ~111 day growing season · Full guide →

Last frost: May 22 · First frost: September 10 · 111 day season

Activity When Date Range
Direct Sow April 10 Apr 10 – May 1
Bloom June 19 Jun 19 – Jul 17
Zone 3b ~135 day growing season · Full guide →

Last frost: May 10 · First frost: September 22 · 135 day season

Activity When Date Range
Direct Sow April 5 Apr 5 – Apr 26
Bloom June 14 Jun 14 – Jul 26
Zone 4a ~145 day growing season · Full guide →

Last frost: May 6 · First frost: September 28 · 145 day season

Activity When Date Range
Direct Sow April 1 Apr 1 – Apr 22
Bloom June 10 Jun 10 – Jul 22
Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity When Date Range
Direct Sow April 3 Apr 3 – Apr 24
Bloom June 12 Jun 12 – Jul 31
Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity When Date Range
Direct Sow March 28 Mar 28 – Apr 18
Bloom June 6 Jun 6 – Aug 1
Zone 5b ~178 day growing season · Full guide →

Last frost: April 18 · First frost: October 13 · 178 day season

Activity When Date Range
Direct Sow March 21 Mar 21 – Apr 11
Bloom May 30 May 30 – Jul 25
Zone 6b ~205 day growing season · Full guide →

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

Activity When Date Range
Direct Sow March 6 Mar 6 – Mar 27
Bloom May 15 May 15 – Jul 10
Zone 7a ~221 day growing season · Full guide →

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

Activity When Date Range
Direct Sow February 25 Feb 25 – Mar 18
Bloom May 6 May 6 – Jul 15
Fall Sowing August 23 Aug 23 – Sep 6
Zone 7b ~235 day growing season · Full guide →

Last frost: March 18 · First frost: November 8 · 235 day season

Activity When Date Range
Direct Sow February 18 Feb 18 – Mar 11
Bloom April 29 Apr 29 – Jul 22
Fall Sowing August 30 Aug 30 – Sep 13
Zone 8a ~255 day growing season · Full guide →

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

Activity When Date Range
Direct Sow February 8 Feb 8 – Mar 1
Bloom April 19 Apr 19 – Jul 26
Fall Sowing September 9 Sep 9 – Sep 23

Growing Tips for Alaska

Larkspur does not transplant well — direct-sow only. In cold climates (zones 2–6), sow directly in early spring as soon as soil can be worked, 4–6 weeks before last frost; cold soil improves germination. In zones 7–10, fall-sow 8–10 weeks before first frost for spring bloom. Press seeds lightly into soil; they need darkness to germinate — cover with 1/8–1/4 inch of soil. Thin to 6–12 inches to prevent powdery mildew. Allow seed pods to mature and self-sow for naturalized colonies. All parts are toxic if ingested.

Frequently Asked Questions

When should I plant Larkspur in Alaska?

Planting dates for Larkspur in Alaska depend on your USDA zone. Alaska spans zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Alaska for planting?

Alaska contains USDA hardiness zones 2a, 2b, 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. 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.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: July 2026.