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When to Plant Sweet Alyssum in Minnesota

Sweet Alyssum (Lobularia maritima) is a low-growing cool-season annual prized for its honey-scented clusters of tiny white, pink, or purple flowers. A workhorse border plant, it tolerates light frost, self-seeds readily, and attracts beneficial insects throughout its bloom season. In warm climates it often re-blooms in fall after summer heat fades.

Minnesota spans USDA hardiness zones 3b, 4a, 4b, 5a (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 Sweet Alyssum planting dates based on your local frost dates.

Sweet Alyssum Planting Calendar for Minnesota

Zone 3b ~135 day growing season · Full guide →

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

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 10 May 10 – May 31
Bloom June 21 Jun 21 – Aug 16
Zone 4a ~145 day growing season · Full guide →

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

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Bloom June 17 Jun 17 – Aug 19
Zone 4b ~155 day growing season · Full guide →

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

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Bloom June 12 Jun 12 – Aug 14
Zone 5a ~166 day growing season · Full guide →

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

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 11 Apr 11 – May 2
Bloom June 6 Jun 6 – Aug 15

Growing Tips for Minnesota

Surface-sow seeds — they need light to germinate. Direct-sow as soon as soil can be worked in spring; in zones 7+ also sow in fall. Thin to 6 inches apart. Shear back hard in midsummer when heat causes dormancy — plants recover and re-bloom when cool weather returns. Self-seeds prolifically; allow a few plants to set seed for a perpetual colony.

Frequently Asked Questions

When should I plant Sweet Alyssum in Minnesota?

Planting dates for Sweet Alyssum in Minnesota depend on your USDA zone. Minnesota spans zones 3b, 4a, 4b, 5a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Minnesota for planting?

Minnesota contains USDA hardiness zones 3b, 4a, 4b, 5a. 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.