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When to Plant Larkspur in Wisconsin

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.

Wisconsin spans USDA hardiness zones 4a, 4b, 5a, 5b, 6a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

Find Your County

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

Larkspur Planting Calendar for Wisconsin

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 6a ~193 day growing season · Full guide →

Last frost: April 10 · First frost: October 20 · 193 day season

Activity When Date Range
Direct Sow March 13 Mar 13 – Apr 3
Bloom May 22 May 22 – Jul 17

Growing Tips for Wisconsin

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 Wisconsin?

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

What zone is Wisconsin for planting?

Wisconsin contains USDA hardiness zones 4a, 4b, 5a, 5b, 6a. 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: June 2026.