When to Plant Shiso in St. Clair County, MI
Shiso (perilla) is a fragrant Japanese herb with large, ruffled leaves in green or purple varieties. It has a unique flavor combining mint, basil, and anise.
St. Clair County, Michigan is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 27, giving you a growing season of approximately 183 days.
At an elevation of 1,065 feet, St. Clair County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Shiso during the growing season.
St. Clair County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Shiso Planting Timeline — St. Clair County, MI
Shiso Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | July 6 | Jul 6 – Aug 31 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
50–70 days
Soil pH
5.5 – 7
USDA Zone
Zone 5b
Growing Season
183 days
Growing Tips for St. Clair County
Direct sow after last frost or start indoors. Both green and red varieties are available. Pinch tips to encourage bushiness. Self-sows prolifically; deadhead to control.
Companion Planting
Good Companions
Level Up Your Garden
Shiso in Other Locations
Frequently Asked Questions
When should I plant Shiso in St. Clair County, MI?
St. Clair County is in Zone 5b with an average last frost of April 27. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Clair County, MI?
St. Clair County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 27.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help St. Clair County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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