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When to plant Foxglove in Clark County County,

Foxglove planted in Clark County County between April 21 and May 12 matures in 120 days — well before the October 17 first frost.

When to Plant Foxglove in Clark County, IL

Clark County, Illinois Zone 6b June

June in the garden — Clark County, Illinois

We've pulled the most time-sensitive tasks for Clark County, Illinois this June and put them front and centre. Tackle them in order.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Time to start foxglove inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Basket week: foxglove

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

To set up a strong July, finish these tasks
  • 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.

Clark County, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 591 feet, Clark County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Foxglove during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Clark County, IL (Zone 6b) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17
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Clark 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 (88 days to spare)
Start indoors: Feb 5 Transplant: Apr 16 🌸 Bloom: Jun 11 – Jul 16
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Feb 10 Transplant: Apr 21 🌸 Bloom: Jun 16 – Jul 21
Safe Start (90%) ✓ Fits season (88 days to spare)
Start indoors: Feb 24 Transplant: May 5 🌸 Bloom: Jun 30 – Aug 4

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 Clark 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 Clark County is excellent for Foxglove — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) — 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 186-day season

Sow every 9.1 weeks. Last sowing by Jun 19 to harvest before frost.

Foxglove Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 129 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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 4.3" 0" ✅ Rainfall sufficient
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clark 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 ~1,750 GDD — county provides 3,255 GDD Excellent fit

Foxglove Planting Timeline — Clark County, IL

Foxglove Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 21 Apr 21 – May 12
Bloom June 16 Jun 16 – Jul 21

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

186 days in Clark County

Growing Tips for Foxglove in Clark County

Direct sow Foxglove outdoors after April 14 in Clark 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 Clark County, IL?

Clark County is in Zone 6b with an average last frost of April 14. Plan your Foxglove planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, IL?

Clark County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 17.

When should I plant Foxglove in Clark County, ?

In Clark County, , plant Foxglove after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Clark County, for Foxglove?

Clark County sits in USDA Zone 6b. Foxglove grows reliably in zones 3a through 9a, so it's a good fit here.

Can Foxglove grow in Clark County's climate?

Yes — Foxglove grows well in Clark County's temperate climate. Clark County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.

🌱

Your Clark County Garden Planner — Free

A 22-page printable planner built for Clark County (Zone 6b). 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 Clark County, IL. 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.