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When to Plant Gladiolus in Klamath County, OR

Klamath County, Oregon Zone 6b June

Your June planting checklist for Klamath County, Oregon

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

Avg. last frost June 13
Avg. first frost September 21
Soil temp (4") 72°F
Watering High
Pest pressure High
Daylight 15.1 hrs
  1. Set out gladiolus seedlings

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant gladiolus from seed, right in the garden

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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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.

Klamath County, Oregon is in USDA Zone 6b. The average last spring frost is June 13 and the first fall frost is September 21, giving you a growing season of approximately 100 days.

At an elevation of 142 feet, Klamath County receives approximately 48.7 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
Klamath County, OR (Zone 6b) Short season
100 days
Last Spring Frost June 13
100 growing days
First Fall Frost September 21
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Klamath County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 30 🌸 Bloom: Aug 15 – Dec 5
Recommended (50%) ✗ May not fit
Transplant: Jun 13 🌸 Bloom: Aug 29 – Dec 19
Safe Start (90%) ✓ Fits season (290 days to spare)
Transplant: Jun 26 🌸 Bloom: Sep 11 – Jan 1

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 Klamath County

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

Soil pH

Your soil pH (5.5–6.3) is more acidic than Gladiolus prefers (6.0–6.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Gladiolus.

Organic Matter

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

How to Plant Gladiolus

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

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
2.1″/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 7.4" 0" ❄️ Dormant
Feb 5.2" 0" ❄️ Dormant
Mar 4.8" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 3" 0" ❄️ Dormant
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 0.9" 3.4" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.8" 0" ❄️ Dormant
Nov 7.7" 0" ❄️ Dormant
Dec 6.9" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Klamath 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 1,225 GDD Good fit

Gladiolus Planting Timeline — Klamath County, OR

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors June 13 Jun 13 – Jun 27
Direct Sow June 13 Jun 13 – Jul 4
Bloom August 29 Aug 29 – Dec 19

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6b

📆 Growing Season

100 days in Klamath County

Growing Tips for Gladiolus in Klamath County

Direct sow Gladiolus outdoors after June 13 in Klamath County when soil has warmed and frost danger has passed.

Your 100.0-day growing season in Klamath County is tight for Gladiolus (70.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Klamath County, OR?

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

What planting zone is Klamath County, OR?

Klamath County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 13 and first fall frost is September 21.

🌱

Your Klamath County Garden Planner — Free

A 22-page printable planner built for Klamath 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 Klamath County, OR. 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.