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When to plant Gladiolus in Macoupin County County,

The best window to plant Gladiolus in Macoupin County County, is April 11–May 2, when soil warms to 50°F. Last frost typically hits April 11; first frost October 21.

When to Plant Gladiolus in Macoupin County, IL

Macoupin County, Illinois Zone 6b June

What to do in June

Here's what deserves your attention in Macoupin County, Illinois this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 11
Avg. first frost October 21
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Bring in the gladiolus

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong July, finish these tasks
  • First harvests: gladiolus

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Gladiolus (Gladiolus spp.) produce tall, stately spikes of trumpet-shaped blooms in a rich array of colors, making them one of the most popular cut flowers in the world. Each spike carries 12–20 florets that open in succession from bottom to top over 7–10 days. By planting corms every two weeks from last frost through early summer, gardeners create a continuous succession of fresh blooms from midsummer through fall. Corms multiply each season — a single planting becomes a growing collection over the years. Ideal for back-of- border planting, cutting gardens, and mixed summer containers.

Macoupin County, Illinois is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 21, giving you a growing season of approximately 193 days.

At an elevation of 859 feet, Macoupin County receives approximately 30.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Gladiolus during the growing season.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Macoupin County, IL (Zone 6b) Moderate season
193 days
Last Spring Frost April 11
193 growing days
First Fall Frost October 21

Macoupin County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: Apr 4 🌸 Bloom: Jun 20 – Oct 10
Recommended (50%) ✓ Fits season (4 days to spare)
Transplant: Apr 11 🌸 Bloom: Jun 27 – Oct 17
Safe Start (90%) ✓ Fits season (9 days to spare)
Transplant: Apr 20 🌸 Bloom: Jul 6 – Oct 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 Macoupin County

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

Soil pH

Your soil pH (6.0–7.2) is more alkaline than Gladiolus prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Gladiolus will thrive.

How to Plant Gladiolus

5"
Planting Depth
5"
Between Plants
12"
Between Rows

Succession Planting Gladiolus

3
successive plantings in your 193-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 563 gal / 100 sq ft

Monthly Watering Guide for Gladiolus

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

Month Gladiolus Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Gladiolus 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.

Gladiolus needs ~1,488 GDD — county provides 3,377 GDD Excellent fit

Gladiolus Planting Timeline — Macoupin County, IL

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 11 Apr 11 – May 2
Bloom June 27 Jun 27 – Oct 17

Plant 5" deep · 5" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

193 days in Macoupin County

Growing Tips for Gladiolus in Macoupin County

Direct sow Gladiolus outdoors after April 11 in Macoupin County when soil has warmed and frost danger has passed.

General growing tips

Plant corms 4–6 inches deep, pointed end up, as soon as soil reaches 60°F after last frost. Space 4–6 inches apart; rows 12 inches apart. Stake or grow through a support grid — tall varieties reach 4–5 feet and tip in wind. Begin succession plantings every 2 weeks through early July for continuous bloom. Water deeply once a week; mulch to conserve moisture and suppress weeds. Cut spikes for vases when the lowest floret just begins to open. After first killing frost (in cold zones), dig corms, let dry for 3–4 weeks in a ventilated spot, remove cormels, and store in mesh bags at 35–50°F. In zones 7b–8a, corms sometimes survive mild winters in ground with heavy mulch; in zones 8b+, in-ground overwintering is reliable.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Gladiolus in Macoupin County, IL?

Macoupin County is in Zone 6b with an average last frost of April 11. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Macoupin County, IL?

Macoupin County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 21.

When should I plant Gladiolus in Macoupin County, ?

In Macoupin County, , plant Gladiolus after the last frost (around April 11) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Macoupin County, for Gladiolus?

Macoupin County sits in USDA Zone 6b. Gladiolus grows reliably in zones 3a through 10b, so it's a good fit here.

Can Gladiolus grow in Macoupin County's climate?

Yes — Gladiolus grows well in Macoupin County's temperate climate. Macoupin County averages a 193-day frost-free season, with last frost around April 11 and first frost around October 21.

🌱

Your Macoupin County Garden Planner — Free

A 22-page printable planner built for Macoupin 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 Macoupin 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.