Perennial

When to Plant Hostas in Idaho

The king of shade gardens. Hostas come in hundreds of varieties and get more beautiful with each passing year.

The Short Answer

In Idaho, plant hostas based on your regional frost dates. Northern Idaho has a last frost around May 5 - May 25, while Eastern Idaho sees frost end around May 20 - Jun 10. Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations.

Idaho Frost Dates

Your planting dates depend on which part of Idaho you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Northern Idaho 5a, 5b, 6a May 5 - May 25 Sep 15 - Oct 5
Boise Area 6b, 7a Apr 20 - May 5 Oct 5 - Oct 20
Eastern Idaho 3b, 4a, 4b, 5a May 20 - Jun 10 Sep 1 - Sep 20

Hostas Planting Schedule for Idaho

Northern Idaho (Zones 5a, 5b, 6a)

Average last frost: May 5 - May 25 · Average first frost: Sep 15 - Oct 5

Transplant Outside
0 wks after frost

Boise Area (Zones 6b, 7a)

Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20

Transplant Outside
0 wks after frost

Eastern Idaho (Zones 3b, 4a, 4b, 5a)

Average last frost: May 20 - Jun 10 · Average first frost: Sep 1 - Sep 20

Transplant Outside
0 wks after frost

Growing Hostas in Idaho

Hostas in Idaho's Climate

Your climate is hosta heaven. Cold winters provide necessary dormancy, moderate summers prevent heat scorch, and abundant shade from deciduous forests creates ideal growing conditions. Michigan, Minnesota, and Wisconsin grow some of the finest hostas in the country. The only pest concern is slugs — iron phosphate bait handles them.

Soil Considerations for Idaho

Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas.

Idaho Climate & Growing Season

Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations. Hostas can handle frost well, which is an advantage in Idaho's climate. You can push planting dates earlier in spring and extend into fall.

Growing season length varies across Idaho: Northern Idaho (5a, 5b, 6a) has a last frost around May 5 - May 25, while Eastern Idaho (3b, 4a, 4b, 5a) sees frost end around May 20 - Jun 10. This difference matters for hostas — adjust your planting dates to match your specific region.

Growing Tips

Plant divisions or nursery plants in spring or fall. Slugs are the main enemy — use iron phosphate bait. Mulch to retain moisture.

Companion Planting

Plant hostas alongside these companions for better growth:

Ferns Astilbe Heuchera

The Bottom Line

Hostas can be grown successfully across Idaho, but your exact planting dates depend on which region you're in. Northern Idaho gardeners should plan around a May 5 - May 25 last frost, while those in Eastern Idaho can typically plant later. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Hostas Growing Guide National planting guide with all states Idaho Planting Calendar All plants for Idaho Hostas in Alabama Alabama planting dates Hostas in Alaska Alaska planting dates Hostas in Arizona Arizona planting dates Hostas in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

Ready to Start Planting?

Enter your zip code and pick your plant. We'll tell you exactly when to plant, start seeds, and harvest — based on where you live.

Find Your Planting Dates