When to Plant Hostas in Florence County, WI
What to do in June
Your Florence County, Wisconsin garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Transplant hostas outside
Your last frost (May 26) has passed. These warm-season crops can handle outdoor soil now.
Hostas (Hosta spp.) are the undisputed kings of the shade garden, grown primarily for their spectacular mounded foliage in shades of deep green, blue-green, gold, and variegated combinations. Originating in East Asia (Japan, China, Korea), hostas form dense, long-lived clumps that reliably return year after year with minimal care. In summer, tall scapes of lavender or white tubular flowers rise above the foliage — some cultivars (notably H. plantaginea hybrids) are notably fragrant. Extremely adaptable in moist, well-drained soil with consistent shade to part shade.
Florence County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.
At an elevation of 1,147 feet, Florence County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Hostas to ensure they mature before fall.
Florence County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.8
Drainage
Well Drained
Hostas 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 Florence County
How your county's soil matches Hostas's growing requirements.
Soil pH
Your soil pH (5.8–6.8) overlaps with Hostas's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Florence County is excellent for Hostas — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Hostas will thrive.
How to Plant Hostas
Succession Planting Hostas
Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.
Hostas Water Budget
Monthly Watering Guide for Hostas
Hostas needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Hostas Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 3.4" | 0" | ❄️ Dormant |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Aug | 4.3" | 4" | 0.3" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | — | 2.7" | 0" | ❄️ Dormant |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Florence County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Hostas 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.
Hostas Planting Timeline — Florence County, WI
Hostas Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 10 | Mar 10 – Mar 24 |
| Transplant Outdoors | June 9 | Jun 9 – Jun 23 |
| Bloom | September 8 | Sep 8 – Nov 17 |
Plant 1" deep · 24" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
118 days in Florence County
Growing Tips for Hostas in Florence County
Direct sow Hostas outdoors after May 26 in Florence County when soil has warmed and frost danger has passed.
General growing tips
Plant bare-root crowns or divisions in early spring just as new growth emerges, or in fall at least 6 weeks before hard freeze. Choose a site with morning sun and afternoon shade in Zones 6+; deeper shade is acceptable but reduces vigor and bloom. Keep consistently moist but never waterlogged. Apply a 2–3 inch mulch layer to conserve moisture and suppress weeds. Slugs are the primary pest — use iron phosphate bait if damage is significant. Deer will browse hostas heavily in most regions; protect with fencing or repellents. Divide every 3–5 years in spring to rejuvenate. Fall planting (Zones 4+) is equally effective as spring planting when soil stays workable. Year 2+ plants reach full size and flower most reliably; first-year divisions may produce limited flower spikes.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Hostas in Other Locations
Frequently Asked Questions
When should I plant Hostas in Florence County, WI?
Florence County is in Zone 4b with an average last frost of May 26. Plan your Hostas planting based on this frost date — see the calendar above for exact timing.
What planting zone is Florence County, WI?
Florence County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 26 and first fall frost is September 21.
Your Florence County Garden Planner — Free
A 22-page printable planner built for Florence 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.