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When to plant Gladiolus in Union County County,

Gladiolus planted in Union County County between April 11 and May 2 matures in 100 days — well before the October 23 first frost.

When to Plant Gladiolus in Union County, GA

Union County, Georgia Zone 7b June

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Avg. last frost April 11
Avg. first frost October 23
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
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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.

Union County, Georgia is in USDA Zone 7b. The average last spring frost is April 11 and the first fall frost is October 23, giving you a growing season of approximately 195 days.

At an elevation of 175 feet, Union County receives approximately 61.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Gladiolus during the growing season. Clay soil retains moisture well for Gladiolus, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Gladiolus root diseases.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Union County, GA (Zone 7b) Moderate season
195 days
Last Spring Frost April 11
195 growing days
First Fall Frost October 23
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Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.2

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Mar 31 🌸 Bloom: Jun 9 – Oct 27
Recommended (50%) ✗ May not fit
Transplant: Apr 11 🌸 Bloom: Jun 20 – Nov 7
Safe Start (90%) ✗ May not fit
Transplant: May 3 🌸 Bloom: Jul 12 – Nov 29

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 Union County

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

Soil pH

Your soil pH (5.8–6.2) overlaps with Gladiolus's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Gladiolus.

How to Plant Gladiolus

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

Succession Planting Gladiolus

3
successive plantings in your 195-day season

Sow every 8 weeks. Last sowing by Jul 15 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 6" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 5.8" 0" ❄️ Dormant
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.7" 0" ✅ Rainfall sufficient
Aug 4.3" 6.2" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 5.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union 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 ~1,679 GDD — county provides 3,851 GDD Excellent fit

Gladiolus Planting Timeline — Union County, GA

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 20 Jun 20 – Nov 7

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 Bloom
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

195 days in Union County

Growing Tips for Gladiolus in Union County

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

With Union County's clay soil (28% clay), work in 3-4 inches of compost before planting Gladiolus. Avoid tilling when soil is wet to prevent compaction.

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 Union County, GA?

Union County is in Zone 7b 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 Union County, GA?

Union County, Georgia is in USDA Hardiness Zone 7b. The average last spring frost is April 11 and first fall frost is October 23.

When should I plant Gladiolus in Union County, ?

In Union County, , plant Gladiolus after the last frost (around April 11) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Union County, for Gladiolus?

Union County sits in USDA Zone 7b. Gladiolus grows reliably in zones 3a through 10b, so it's a good fit here.

Can Gladiolus grow in Union County's climate?

Yes — Gladiolus grows well in Union County's temperate climate. Union County averages a 195-day frost-free season, with last frost around April 11 and first frost around October 23.

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Your Union County Garden Planner — Free

A 22-page printable planner built for Union County (Zone 7b). 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 Union County, GA. 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.