When to Plant Hyssop in Eau Claire County, WI
May in the garden — Eau Claire County, Wisconsin
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Plant out hyssop
Frost risk is low now in Eau Claire County, Wisconsin. If you've been covering beds overnight, you can stop.
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.
Eau Claire County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 3, giving you a growing season of approximately 146 days.
At an elevation of 674 feet, Eau Claire County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Hyssop to ensure they mature before fall.
Eau Claire County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.3
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.
Soil Compatibility in Eau Claire County
How your county's soil matches Hyssop's growing requirements.
Soil pH
Your soil pH (6.2–7.3) is within Hyssop's preferred range (6.0–8.0).
Soil Texture
The silt loam soil in Eau Claire County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Hyssop.
Organic Matter
Organic matter is excellent (4.2%) — Hyssop will thrive.
How to Plant Hyssop
Succession Planting Hyssop
Sow every 8 weeks. Last sowing by Jul 05 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Hyssop
Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Hyssop Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 2.2" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 3.5" | 0" | ❄️ Dormant |
| May | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Eau Claire County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Hyssop Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Hyssop Planting Timeline — Eau Claire County, WI
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Harvest | July 26 | Jul 26 – Sep 27 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
146 days in Eau Claire County
Growing Tips for Hyssop in Eau Claire County
Direct sow Hyssop outdoors after May 10 in Eau Claire County when soil has warmed and frost danger has passed.
General growing tips
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 Eau Claire County, WI?
Eau Claire County is in Zone 4b with an average last frost of May 10. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Eau Claire County, WI?
Eau Claire County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 3.
Your Eau Claire County Garden Planner — Free
A 24-page printable planner built for Eau Claire County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.