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When to plant Foxglove in Jackson County, IL

The best window to plant Foxglove in Jackson County, is April 17–May 8, when soil warms to 50°F. Last frost typically hits April 10; first frost October 21.

When to Plant Foxglove in Jackson County, IL

Jackson County, Illinois Zone 7a July

Your July planting checklist for Jackson County, Illinois

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Jackson County, Illinois.

Avg. last frost April 10
Avg. first frost October 21
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Bring in the foxglove

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

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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.

Jackson County, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 21, giving you a growing season of approximately 194 days.

At an elevation of 1,046 feet, Jackson County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Foxglove during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Jackson County, IL (Zone 7a) Moderate season
194 days
Last Spring Frost April 10
194 growing days
First Fall Frost October 21

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Foxglove Planting Risk Windows

Early Start (70% safe) ✓ Fits season (101 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🌸 Bloom: May 31 – Jul 5
Recommended (50%) ✓ Fits season (103 days to spare)
Start indoors: Feb 13 Transplant: Apr 17 🌸 Bloom: Jun 5 – Jul 10
Safe Start (90%) ✓ Fits season (101 days to spare)
Start indoors: Feb 27 Transplant: May 1 🌸 Bloom: Jun 19 – Jul 24

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 Jackson County

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

Soil pH

Your soil pH (6.1–7.1) is more alkaline than Foxglove prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The silt loam soil in Jackson 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 (4.1%) — 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 194-day season

Sow every 9.1 weeks. Last sowing by Jun 23 to harvest before frost.

Foxglove Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 949 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 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jackson 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 ~1,675 GDD — county provides 3,249 GDD Excellent fit

Foxglove Planting Timeline — Jackson County, IL

Foxglove Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 17 Apr 17 – May 8
Bloom June 5 Jun 5 – Jul 10

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in Jackson County

Growing Tips for Foxglove in Jackson County

Direct sow Foxglove outdoors after April 10 in Jackson 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 Jackson County, IL?

Jackson County is in Zone 7a with an average last frost of April 10. Plan your Foxglove planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jackson County, IL?

Jackson County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 21.

When should I plant Foxglove in Jackson County, IL?

In Jackson County, IL, plant Foxglove after the last frost (around April 10) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Jackson County, IL for Foxglove?

Jackson County sits in USDA Zone 7a. Foxglove grows reliably in zones 3a through 9a, so it's a good fit here.

Can Foxglove grow in Jackson County's climate?

Yes — Foxglove grows well in Jackson County's temperate climate. Jackson County averages a 194-day frost-free season, with last frost around April 10 and first frost around October 21.

🌱

Your Jackson County Garden Planner — Free

A 22-page printable planner built for Jackson County (Zone 7a). 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 Jackson County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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