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When to plant Gladiolus in Sumner County, KS

Gladiolus planted in Sumner County between April 11 and May 2 matures in 70–100 days — well before the October 26 first frost.

When to Plant Gladiolus in Sumner County, KS

Sumner County, Kansas Zone 7a July

What to do in July

We've pulled the most time-sensitive tasks for Sumner County, Kansas this July and put them front and centre. Tackle them in order.

Avg. last frost April 11
Avg. first frost October 26
Soil temp (4") 80°F
Watering Moderate
Pest pressure High
Daylight 14.3 hrs
  1. Harvest gladiolus as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to August
  • 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.

Sumner County, Kansas is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 26, giving you a growing season of approximately 198 days.

At an elevation of 637 feet, Sumner County receives approximately 29 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Gladiolus during the growing season.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Sumner County, KS (Zone 7a) Moderate season
198 days
Last Spring Frost April 11
198 growing days
First Fall Frost October 26

Sumner County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Transplant: Apr 5 🌸 Bloom: Jun 14 – Oct 18
Recommended (50%) ✓ Fits season (2 days to spare)
Transplant: Apr 11 🌸 Bloom: Jun 20 – Oct 24
Safe Start (90%) ✓ Fits season (5 days to spare)
Transplant: Apr 25 🌸 Bloom: Jul 4 – Nov 7

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 Sumner County

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

Soil pH

Your soil pH (6.4–7.8) is more alkaline than Gladiolus prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). 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 198-day season

Sow every 8 weeks. Last sowing by Jul 18 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 814 gal / 100 sq ft
Drought risk

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

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 0.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.4" 0.9" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sumner 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 ~1,169 GDD — county provides 2,722 GDD Excellent fit

Gladiolus Planting Timeline — Sumner County, KS

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 – Oct 24

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 7a

📆 Growing Season

198 days in Sumner County

Growing Tips for Gladiolus in Sumner County

Direct sow Gladiolus outdoors after April 11 in Sumner 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 Sumner County, KS?

Sumner County is in Zone 7a 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 Sumner County, KS?

Sumner County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 26.

When should I plant Gladiolus in Sumner County, KS?

In Sumner County, KS, plant Gladiolus after the last frost (around April 11) and before the first frost (around October 26). Best results when soil holds above 50°F.

What growing zone is Sumner County, KS for Gladiolus?

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

Can Gladiolus grow in Sumner County's climate?

Yes — Gladiolus grows well in Sumner County's temperate climate. Sumner County averages a 198-day frost-free season, with last frost around April 11 and first frost around October 26.

🌱

Your Sumner County Garden Planner — Free

A 22-page printable planner built for Sumner 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 Sumner County, KS. 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.