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When to Plant Larkspur in North Dakota

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.

North Dakota spans USDA hardiness zones 3b, 4a, 4b (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.

Larkspur Planting Calendar for North Dakota

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

Growing Tips for North Dakota

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 North Dakota?

Planting dates for Larkspur in North Dakota depend on your USDA zone. North Dakota spans zones 3b, 4a, 4b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is North Dakota for planting?

North Dakota contains USDA hardiness zones 3b, 4a, 4b. 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.