When to plant Hyssop in Douglas County, MN
Plant Hyssop in Douglas County, between May 10 and May 24 — the only viable window. Zone 4b's short season (154 frost-free days) rules out a fall crop.
When to Plant Hyssop in Douglas County, MN
Your July game plan for Douglas County, Minnesota
A quick July briefing for Douglas County, Minnesota gardeners — what's urgent, what's next, and what can wait.
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Harvest hyssop as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Before August arrives, get these ready
- First harvests: hyssop
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.
Douglas County, Minnesota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 4, giving you a growing season of approximately 154 days.
At an elevation of 1,010 feet, Douglas County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Hyssop to ensure they mature before fall.
Douglas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.9
Drainage
Well Drained
Hyssop 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 Douglas County
How your county's soil matches Hyssop's growing requirements.
Soil pH
Your soil pH (5.8–6.9) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.
Soil Texture
The silt loam soil in Douglas County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.
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 06 to harvest before frost.
Hyssop 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 3.4" | 0" | ❄️ Dormant |
| May | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Douglas 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 — Douglas County, MN
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Harvest | July 19 | Jul 19 – Sep 20 |
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: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
154 days in Douglas County
Growing Tips for Hyssop in Douglas County
Direct sow Hyssop outdoors after May 03 in Douglas 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 Douglas County, MN?
Douglas County is in Zone 4b with an average last frost of May 3. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Douglas County, MN?
Douglas County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 4.
When should I plant Hyssop in Douglas County, MN?
In Douglas County, MN, plant Hyssop after the last frost (around May 3) and before the first frost (around October 4). Best results when soil holds above 50°F.
What growing zone is Douglas County, MN for Hyssop?
Douglas County sits in USDA Zone 4b. Hyssop grows reliably in zones 3a through 9b, so it's a good fit here.
Can Hyssop grow in Douglas County's climate?
Yes — Hyssop grows well in Douglas County's temperate climate. Douglas County averages a 154-day frost-free season, with last frost around May 3 and first frost around October 4.
Your Douglas County Garden Planner — Free
A 22-page printable planner built for Douglas 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.