When to plant Hyssop in Cook County, IL
Cook County's 177-day season only supports one Hyssop planting per year. Sow between April 30 and May 14 for the best chance at full maturity before October 17.
When to Plant Hyssop in Cook County, IL
Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.
Cook County, Illinois is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 17, giving you a growing season of approximately 177 days.
At an elevation of 728 feet, Cook County receives approximately 35.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Hyssop during the growing season.
Cook County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Hyssop Planting Timeline — Cook County, IL
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 30 | Apr 30 – May 14 |
| Harvest | July 9 | Jul 9 – Sep 10 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 6a
📆 Growing Season
177 days in Cook County
Growing Tips for Cook County
Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Hyssop in Other Locations
Frequently Asked Questions
When should I plant Hyssop in Cook County, IL?
Cook County is in Zone 6a with an average last frost of April 23. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cook County, IL?
Cook County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 17.
When should I plant Hyssop in Cook County, IL?
In Cook County, IL, plant Hyssop after the last frost (around April 23) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Cook County, IL for Hyssop?
Cook County sits in USDA Zone 6a. Hyssop grows reliably in zones 3a through 9b, so it's a good fit here.
Can Hyssop grow in Cook County's climate?
Yes — Hyssop grows well in Cook County's temperate climate. Cook County averages a 177-day frost-free season, with last frost around April 23 and first frost around October 17.
Your Cook County Garden Planner — Free
A 22-page printable planner built for Cook County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.