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When to plant Impatiens in Lee County County,

Lee County County's short 175-day growing season means one Impatiens planting between April 29 and May 13. No fall crop in Zone 5b.

When to Plant Impatiens in Lee County, IL

Lee County, Illinois Zone 5b June

Lee County, Illinois gardeners: here's your June plan

Your garden in Lee County, Illinois is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 22
Avg. first frost October 14
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Start impatiens under lights

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

A few tasks this June that'll pay off in July
  • First harvests: impatiens

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Impatiens (Impatiens walleriana) are the go-to annual for shaded beds and containers. They produce a continuous carpet of flat-faced blooms from transplant until frost, needing little deadheading. Their preference for consistent moisture and part-shade makes them ideal under trees and along north-facing borders.

Lee County, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 1,010 feet, Lee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Impatiens to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly
Lee County, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14
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Lee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Feb 20 Transplant: Apr 24 🌸 Bloom: Jul 3 – Oct 2
Recommended (50%) ✓ Fits season (7 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🌸 Bloom: Jul 8 – Oct 7
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Mar 10 Transplant: May 12 🌸 Bloom: Jul 21 – Oct 20

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 Lee County

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

Soil pH

Your soil pH (6.3–6.9) is more alkaline than Impatiens prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Impatiens.

Organic Matter

Organic matter is excellent (4.8%) — Impatiens will thrive.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

3
successive plantings in your 175-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Impatiens 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 923 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Impatiens

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

Month Impatiens Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

Impatiens 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.

Impatiens needs ~878 GDD — county provides 2,275 GDD Excellent fit

Impatiens Planting Timeline — Lee County, IL

Impatiens Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 29 Apr 29 – May 13
Bloom July 8 Jul 8 – Oct 7

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Lee County

Growing Tips for Impatiens in Lee County

Direct sow Impatiens outdoors after April 22 in Lee County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost at 70–75°F; germination requires light — do not cover seeds. Transplant after last frost once nights consistently exceed 50°F. Water regularly — wilting causes bud drop and they rarely fully recover the same flush. Watch for impatiens downy mildew (IDM); consider New Guinea impatiens as a resistant alternative in affected regions. Pinch tips at planting to encourage branching.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Impatiens in Lee County, IL?

Lee County is in Zone 5b with an average last frost of April 22. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lee County, IL?

Lee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 14.

When should I plant Impatiens in Lee County County, ?

In Lee County County, , plant Impatiens after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Lee County County, for Impatiens?

Lee County County sits in USDA Zone 5b. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.

Can Impatiens grow in Lee County County's climate?

Yes — Impatiens grows well in Lee County County's temperate climate. Lee County County averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.

🌱

Your Lee County Garden Planner — Free

A 22-page printable planner built for Lee 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 Lee 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.