When to Plant Portulaca in Alaska

Portulaca (Portulaca grandiflora), commonly called moss rose, is a succulent- stemmed annual built for hot, dry, low-fertility conditions where other flowers fail. Its silky, rose-like blooms open in full sun and close at night or on cloudy days. Excellent for slopes, rock gardens, containers, and parking-strip plantings where irrigation is limited. One of the easiest annuals for neglect- proof summer color.

Alaska spans USDA hardiness zones 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a (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 Portulaca planting dates based on your local frost dates.

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

Portulaca Planting Calendar for Alaska

▸ 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 29	Mar 29 – Apr 12
Transplant Outdoors	May 31	May 31 – Jun 14
Direct Sow	May 31	May 31 – Jun 21
Bloom	July 19	Jul 19 – Sep 20

▸ 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 25	Mar 25 – Apr 8
Transplant Outdoors	May 20	May 20 – Jun 3
Direct Sow	May 20	May 20 – Jun 10
Bloom	July 8	Jul 8 – Sep 16

▸ 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 27	Mar 27 – Apr 10
Transplant Outdoors	May 15	May 15 – May 29
Direct Sow	May 15	May 15 – Jun 5
Bloom	July 3	Jul 3 – Sep 18

▸ 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 21	Mar 21 – Apr 4
Transplant Outdoors	May 9	May 9 – May 23
Direct Sow	May 9	May 9 – May 30
Bloom	June 27	Jun 27 – Sep 26

▸ 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	March 14	Mar 14 – Mar 28
Transplant Outdoors	April 25	Apr 25 – May 9
Direct Sow	April 25	Apr 25 – May 16
Bloom	June 13	Jun 13 – Sep 19

▸ 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 27	Feb 27 – Mar 13
Transplant Outdoors	April 10	Apr 10 – Apr 24
Direct Sow	April 10	Apr 10 – May 1
Bloom	May 29	May 29 – Sep 18

▸ 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 25	Feb 25 – Mar 11
Transplant Outdoors	March 25	Mar 25 – Apr 8
Direct Sow	March 25	Mar 25 – Apr 15
Bloom	May 13	May 13 – Sep 9

▸ 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 18	Feb 18 – Mar 4
Transplant Outdoors	March 18	Mar 18 – Apr 1
Direct Sow	March 18	Mar 18 – Apr 8
Bloom	May 6	May 6 – Sep 16

▸ 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	February 8	Feb 8 – Feb 22
Transplant Outdoors	March 1	Mar 1 – Mar 15
Direct Sow	March 1	Mar 1 – Mar 22
Bloom	April 19	Apr 19 – Sep 13

Growing Tips for Alaska

Direct-sow after last frost once soil warms to 65°F, or start indoors 4–6 weeks before last frost. Seed is tiny — surface sow and do not cover. Thin to proper spacing after germination. Thrives in poor, well-drained soil; rich or wet soil produces lush foliage but fewer blooms. No deadheading required — plants are self-cleaning. Double-flowered varieties hold blooms open longer in overcast conditions.

Portulaca in Other States

Frequently Asked Questions

When should I plant Portulaca in Alaska?

Planting dates for Portulaca in Alaska depend on your USDA zone. Alaska spans zones 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Alaska for planting?

Alaska contains USDA hardiness zones 3b, 4a, 4b, 5a, 5b, 6b, 7a, 7b, 8a. 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