When to Plant Sweet Alyssum in Washington

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.

Washington spans USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b, 9a (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 Washington

▸ 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

▸ Zone 6b ~205 day growing season · Full guide →

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

Activity	When	Date Range
Start Indoors	February 20	Feb 20 – Mar 6
Transplant Outdoors	April 3	Apr 3 – Apr 17
Direct Sow	March 13	Mar 13 – Apr 3
Bloom	May 15	May 15 – Jul 31

▸ Zone 7a ~221 day growing season · Full guide →

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

Activity	When	Date Range
Start Indoors	February 11	Feb 11 – Feb 25
Transplant Outdoors	March 25	Mar 25 – Apr 8
Direct Sow	February 25	Feb 25 – Mar 18
Bloom	May 6	May 6 – Jul 29
Fall Sowing	September 20	Sep 20 – Oct 4

▸ Zone 7b ~235 day growing season · Full guide →

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

Activity	When	Date Range
Start Indoors	February 4	Feb 4 – Feb 18
Transplant Outdoors	March 18	Mar 18 – Apr 1
Direct Sow	February 18	Feb 18 – Mar 11
Bloom	April 29	Apr 29 – Aug 5
Fall Sowing	September 27	Sep 27 – Oct 11

▸ Zone 8a ~255 day growing season · Full guide →

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

Activity	When	Date Range
Start Indoors	January 25	Jan 25 – Feb 8
Transplant Outdoors	February 22	Feb 22 – Mar 8
Direct Sow	February 1	Feb 1 – Feb 22
Bloom	April 5	Apr 5 – Jul 26
Fall Sowing	September 23	Sep 23 – Oct 7

▸ Zone 8b ~276 day growing season · Full guide →

Last frost: February 25 · First frost: November 28 · 276 day season

Activity	When	Date Range
Start Indoors	January 14	Jan 14 – Jan 28
Transplant Outdoors	February 4	Feb 4 – Feb 18
Direct Sow	January 14	Jan 14 – Feb 4
Bloom	March 18	Mar 18 – Jul 22
Fall Sowing	October 3	Oct 3 – Oct 17

▸ Zone 9a ~303 day growing season · Full guide →

Last frost: February 10 · First frost: December 10 · 303 day season

Activity	When	Date Range
Transplant Outdoors	January 13	Jan 13 – Jan 27
Direct Sow	December 16	Dec 16 – Jan 6
Bloom	February 17	Feb 17 – Jun 2
Fall Sowing	October 1	Oct 1 – Oct 15

Growing Tips for Washington

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.

Sweet Alyssum in Other States

Frequently Asked Questions

When should I plant Sweet Alyssum in Washington?

Planting dates for Sweet Alyssum in Washington depend on your USDA zone. Washington spans zones 6a, 6b, 7a, 7b, 8a, 8b, 9a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Washington for planting?

Washington contains USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b, 9a. 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.

Blog