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When to Plant Foxglove in Dane County, WI

Dane County, Wisconsin Zone 5b June

Your June gardening checklist

Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 30
Avg. first frost October 9
Soil temp (4") 67°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
Looking ahead to July
  • Starting indoors: foxglove
  • First harvests: foxglove

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Foxglove (Digitalis purpurea) is a stately cottage garden classic, sending up dramatic 3–5 foot spires of tubular flowers — spotted purple, pink, white, or cream — in late spring and early summer. Technically biennial (flowering in its second year), foxglove perpetuates itself so freely from self-sown seed that established plantings appear to be permanent perennials. A key source plant for the heart medication digitalis, all parts are highly toxic if ingested. Bumblebees are the primary pollinators, crawling deep into each bell-shaped flower. Partial shade and cool, moist woodland-edge conditions suit foxglove best; it resents heat and drought.

Dane County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.

At an elevation of 649 feet, Dane County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Foxglove during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Dane County, WI (Zone 5b) Moderate season
162 days
Last Spring Frost April 30
162 growing days
First Fall Frost October 9

Dane County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Foxglove Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 21 Transplant: May 9 🌸 Bloom: Jul 4 – Aug 15
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Feb 26 Transplant: May 14 🌸 Bloom: Jul 9 – Aug 20
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Mar 19 Transplant: Jun 4 🌸 Bloom: Jul 30 – Sep 10

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 Dane County

How your county's soil matches Foxglove's growing requirements.

Soil pH

Your soil pH (6.2–6.8) overlaps with Foxglove's range (5.5–6.5), though not a perfect match.

Soil Texture

The silt loam soil in Dane County is excellent for Foxglove — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) — Foxglove will thrive.

How to Plant Foxglove

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Foxglove

2
successive plantings in your 162-day season

Sow every 9.1 weeks. Last sowing by Jun 11 to harvest before frost.

Foxglove Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Foxglove

Foxglove needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Foxglove Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Dane County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Foxglove 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.

Foxglove needs ~1,525 GDD — county provides 2,470 GDD Excellent fit

Foxglove Planting Timeline — Dane County, WI

Foxglove Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 14 May 14 – Jun 4
Bloom July 9 Jul 9 – Aug 20

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Direct Sow
July Bloom
August Bloom
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

162 days in Dane County

Growing Tips for Foxglove in Dane County

Direct sow Foxglove outdoors after April 30 in Dane County when soil has warmed and frost danger has passed.

General growing tips

Sow seeds indoors 8–10 weeks before last frost or direct-sow outdoors in late spring/early summer for next-year bloom (biennial cycle). Surface-sow — seeds need light to germinate. Transplant after last frost into cool, moist, well-amended soil. Morning sun with afternoon shade is ideal; full shade reduces bloom but is tolerated. Keep consistently moist. First-year plants form a basal rosette only; second-year plants produce flower spikes. After bloom, cut the main spike before seed scatters to prevent excessive spreading, or leave some spikes to self-seed for naturalizing. Perennial species (D. grandiflora, D. x mertonensis) maintain clumps without requiring self-seeding. Wear gloves when handling — all plant parts toxic.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Foxglove in Dane County, WI?

Dane County is in Zone 5b with an average last frost of April 30. Plan your Foxglove planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dane County, WI?

Dane County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 9.

🌱

Your Dane County Garden Planner — Free

A 22-page printable planner built for Dane County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Dane County, WI. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.