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When to plant Gladiolus in Calhoun County, IL

In Calhoun County, plant Gladiolus in spring between April 13 and May 4, once soil temps hold above 50°F. Calhoun County's last frost averages April 13, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 70–100 days before the first frost on October 21.

When to Plant Gladiolus in Calhoun County, IL

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.

Calhoun County, Illinois is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 731 feet, Calhoun County receives approximately 32.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Gladiolus during the growing season.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Calhoun County, IL (Zone 6b) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Calhoun County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

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" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.2" 2.1" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Gladiolus Planting Timeline — Calhoun County, IL

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 13 Apr 13 – May 4
Bloom June 29 Jun 29 – Oct 19

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

Moderate — regular watering

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

191 days in Calhoun County

Growing Tips for Calhoun County

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 Calhoun County, IL?

Calhoun County is in Zone 6b with an average last frost of April 13. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calhoun County, IL?

Calhoun County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 13 and first fall frost is October 21.

When should I plant Gladiolus in Calhoun County, IL?

In Calhoun County, IL, plant Gladiolus after the last frost (around April 13) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Calhoun County, IL for Gladiolus?

Calhoun 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 Calhoun County's climate?

Yes — Gladiolus grows well in Calhoun County's temperate climate. Calhoun County averages a 191-day frost-free season, with last frost around April 13 and first frost around October 21.

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Your Calhoun County Garden Planner — Free

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

Sources & credits

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