Perennial Flower

When to Plant Lavender in Idaho

Fragrant, drought-tolerant, and beloved by pollinators. Once established, lavender rewards you for years.

The Short Answer

In Idaho, plant lavender 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

Lavender 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
10 wks before frost
Transplant Outside
2 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
10 wks before frost
Transplant Outside
2 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
10 wks before frost
Transplant Outside
2 wks after frost

Growing Lavender in Idaho

Lavender in Idaho's Climate

Lavender is challenging in cold climates — wet clay soil and cold winters are its enemies. English lavender (Hidcote, Munstead) is hardiest to zone 5. The key is drainage — raised beds with gravel and sand amendment are mandatory. Sandy soils of western Michigan and similar areas have a natural advantage. Mulch with pea gravel, not organic mulch, to prevent crown rot.

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.

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 lavender — adjust your planting dates to match your specific region.

Growing Tips

Needs excellent drainage — clay soil is lavender's enemy. Don't prune into old wood. English varieties (Lavandula angustifolia) are hardiest.

Companion Planting

Plant lavender alongside these companions for better growth:

Roses Thyme Sage

The Bottom Line

Lavender 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

Lavender Growing Guide National planting guide with all states Idaho Planting Calendar All plants for Idaho Lavender in Alabama Alabama planting dates Lavender in Alaska Alaska planting dates Lavender in Arizona Arizona planting dates Lavender 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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