Perennial Flower

When to Plant Black-Eyed Susans in Idaho

Cheerful golden blooms that attract butterflies and tolerate drought. A backbone of the low-maintenance perennial garden.

The Short Answer

In Idaho, plant black-eyed susans 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

Black-Eyed Susans Planting Schedule for Idaho

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

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

Start Seeds Indoors
6 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Boise Area (Zones 6b, 7a)

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

Start Seeds Indoors
6 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

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

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

Start Seeds Indoors
6 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Growing Black-Eyed Susans in Idaho

Black-Eyed Susans in Idaho's Climate

Black-eyed Susans are native wildflowers that thrive in cold-climate conditions. Plant divisions or nursery plants from spring through early fall. They handle poor soil, drought once established, and cold winters without complaint. Leave seed heads standing through winter for bird food and visual interest.

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. Black-Eyed Susans 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 black-eyed susans — but black-eyed susans handle frost well, so the timing difference is less critical.

Growing Tips

Leave seed heads standing through winter for birds and visual interest. Self-seeds freely — deadhead if you don't want more.

Companion Planting

Plant black-eyed susans alongside these companions for better growth:

Coneflowers Ornamental Grasses

The Bottom Line

Black-Eyed Susans 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

Black-Eyed Susans Growing Guide National planting guide with all states Idaho Planting Calendar All plants for Idaho Black-Eyed Susans in Alabama Alabama planting dates Black-Eyed Susans in Alaska Alaska planting dates Black-Eyed Susans in Arizona Arizona planting dates Black-Eyed Susans 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

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