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When to Plant Sweet Alyssum in Maine

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.

Maine spans USDA hardiness zones 4a, 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 Sweet Alyssum planting dates based on your local frost dates.

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

Sweet Alyssum Planting Calendar for Maine

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 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
Zone 5b ~178 day growing season · Full guide →

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

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 4 Apr 4 – Apr 25
Bloom May 30 May 30 – Aug 8
Zone 6a ~193 day growing season · Full guide →

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

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow March 20 Mar 20 – Apr 10
Bloom May 22 May 22 – Jul 31

Growing Tips for Maine

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 Maine?

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

What zone is Maine for planting?

Maine contains USDA hardiness zones 4a, 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.