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When to plant Foxglove in Iroquois County County,

In Iroquois County County, plant Foxglove in spring between May 2 and May 23, once soil temps hold above 50°F. Iroquois County County's last frost averages April 18, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 120 days before the first frost on October 13.

When to Plant Foxglove in Iroquois County, IL

Iroquois County, Illinois Zone 5b June

What to do in June

June is a pivotal month for Iroquois County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 18
Avg. first frost October 13
Soil temp (4") 67°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Start foxglove under lights

    These need a head start before your last frost (April 18). Sow into cells now so you're ready to transplant in a few weeks.

  2. It's harvest week for foxglove

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of July
  • 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.

Iroquois County, Illinois is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 13, giving you a growing season of approximately 178 days.

At an elevation of 1,345 feet, Iroquois County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Foxglove during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Iroquois County, IL (Zone 5b) Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13
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Iroquois County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Foxglove Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Feb 9 Transplant: Apr 27 🌸 Bloom: Jun 22 – Aug 3
Recommended (50%) ✓ Fits season (66 days to spare)
Start indoors: Feb 14 Transplant: May 2 🌸 Bloom: Jun 27 – Aug 8
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Mar 4 Transplant: May 20 🌸 Bloom: Jul 15 – Aug 26

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 Iroquois County

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

Soil pH

Your soil pH (5.9–6.7) overlaps with Foxglove's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Foxglove.

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 178-day season

Sow every 9.1 weeks. Last sowing by Jun 15 to harvest before frost.

Foxglove Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,126 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Iroquois 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 ~1,375 GDD — county provides 2,447 GDD Excellent fit

Foxglove Planting Timeline — Iroquois County, IL

Foxglove Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors May 2 May 2 – May 16
Direct Sow May 2 May 2 – May 23
Bloom June 27 Jun 27 – Aug 8

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

178 days in Iroquois County

Growing Tips for Foxglove in Iroquois County

Direct sow Foxglove outdoors after April 18 in Iroquois 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 Iroquois County, IL?

Iroquois County is in Zone 5b with an average last frost of April 18. Plan your Foxglove planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iroquois County, IL?

Iroquois County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 13.

When should I plant Foxglove in Iroquois County County, ?

In Iroquois County County, , plant Foxglove after the last frost (around April 18) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Iroquois County County, for Foxglove?

Iroquois County County sits in USDA Zone 5b. Foxglove grows reliably in zones 3a through 9a, so it's a good fit here.

Can Foxglove grow in Iroquois County County's climate?

Yes — Foxglove grows well in Iroquois County County's temperate climate. Iroquois County County averages a 178-day frost-free season, with last frost around April 18 and first frost around October 13.

🌱

Your Iroquois County Garden Planner — Free

A 22-page printable planner built for Iroquois 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 Iroquois County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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