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When to plant Gladiolus in Montgomery County County,

Gladiolus planted in Montgomery County County between May 3 and May 24 matures in 100 days — well before the October 7 first frost.

When to Plant Gladiolus in Montgomery County, IA

Montgomery County, Iowa Zone 5b June

Montgomery County, Iowa gardeners: here's your June plan

A quick June briefing for Montgomery County, Iowa gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 26
Avg. first frost October 7
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
Coming up in July — start thinking about
  • 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.

Montgomery County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 7, giving you a growing season of approximately 164 days.

At an elevation of 1,271 feet, Montgomery County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Gladiolus to ensure they mature before fall.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Montgomery County, IA (Zone 5b) Moderate season
164 days
Last Spring Frost April 26
164 growing days
First Fall Frost October 7

Montgomery County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 28 🌸 Bloom: Jul 21 – Oct 20
Recommended (50%) ✗ May not fit
Transplant: May 3 🌸 Bloom: Jul 26 – Oct 25
Safe Start (90%) ✗ May not fit
Transplant: May 19 🌸 Bloom: Aug 11 – Nov 10

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 Montgomery County

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

Soil pH

Your soil pH (6.1–6.8) overlaps with Gladiolus's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Gladiolus will thrive.

How to Plant Gladiolus

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

Succession Planting Gladiolus

2
successive plantings in your 164-day season

Sow every 8 weeks. Last sowing by Jun 29 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 343 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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Montgomery 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 ~1,041 GDD — county provides 2,009 GDD Excellent fit

Gladiolus Planting Timeline — Montgomery County, IA

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors May 3 May 3 – May 17
Direct Sow May 3 May 3 – May 24
Bloom July 26 Jul 26 – Oct 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

164 days in Montgomery County

Growing Tips for Gladiolus in Montgomery County

Direct sow Gladiolus outdoors after April 26 in Montgomery 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 Montgomery County, IA?

Montgomery County is in Zone 5b with an average last frost of April 26. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montgomery County, IA?

Montgomery County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 7.

When should I plant Gladiolus in Montgomery County County, ?

In Montgomery County County, , plant Gladiolus after the last frost (around April 26) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Montgomery County County, for Gladiolus?

Montgomery County County sits in USDA Zone 5b. Gladiolus grows reliably in zones 3a through 10b, so it's a good fit here.

Can Gladiolus grow in Montgomery County County's climate?

Yes — Gladiolus grows well in Montgomery County County's temperate climate. Montgomery County County averages a 164-day frost-free season, with last frost around April 26 and first frost around October 7.

🌱

Your Montgomery County Garden Planner — Free

A 22-page printable planner built for Montgomery 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 Montgomery County, IA. 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.