Blog

When to Plant Lavender in Washtenaw County, MI

Lavender is a fragrant perennial herb with silvery foliage and purple flower spikes. It is prized for its essential oils, culinary uses, and ornamental beauty.

Washtenaw County, Michigan is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 16, giving you a growing season of approximately 170 days.

At an elevation of 737 feet, Washtenaw County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Lavender during the growing season.

Washtenaw County, MI (Zone 6a) Moderate season
170 days
Last Spring Frost April 29
170 growing days
First Fall Frost October 16

Washtenaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 3 🍅 Harvest: Aug 2 – Nov 15
Recommended (50%) ✗ May not fit
Transplant: May 6 🍅 Harvest: Aug 5 – Nov 18
Safe Start (90%) ✗ May not fit
Transplant: May 20 🍅 Harvest: Aug 19 – Dec 2

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Lavender needs ~2,320 GDD — county provides 2,720 GDD Good fit

Lavender Planting Timeline โ€” Washtenaw County, MI

Lavender Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 โ€“ May 20
Harvest August 5 Aug 5 โ€“ Nov 18

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July โ€”
August Harvest
September Harvest
October Harvest
November Harvest
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“200 days

Soil pH

6.5 โ€“ 8

USDA Zone

Zone 6a

Growing Season

170 days

Growing Tips for Washtenaw County

Plant in well-drained, sandy soil. Avoid heavy mulching around the crown. Prune after flowering but do not cut into old wood. Lavender resents wet winter conditions.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Lavender in Washtenaw County, MI?

Washtenaw County is in Zone 6a with an average last frost of April 29. Plan your Lavender planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Washtenaw County, MI?

Washtenaw County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Washtenaw County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Washtenaw County, MI. Local conditions may vary. Last updated: April 2026.