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When to plant Irises in Logan County, KS

Logan County's 165-day season only supports one Irises planting per year. Sow between May 7 and May 21 for the best chance at full maturity before October 12.

When to Plant Irises in Logan County, KS

Logan County, Kansas Zone 6a August

Your August planting checklist for Logan County, Kansas

Welcome to August in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 30
Avg. first frost October 12
Soil temp (4") 77°F
Watering High
Pest pressure High
Daylight 13.5 hrs

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Bearded Iris (Iris germanica) are among the most regal flowers of the late-spring garden, producing elegantly ruffled blooms in virtually every color of the rainbow — often in spectacular bicolor combinations. Named for the fuzzy "beard" on the lower falls (petals), bearded irises grow from thick horizontal rhizomes that spread to form dense clumps over time. Individual blooms last only a few days, but a well-established clump produces successive flowers over 3–4 weeks. Many are intensely fragrant. Native iris species including blue flag iris (I. versicolor) and Virginia iris (I. virginica) are excellent choices for wet or native garden settings.

Logan County, Kansas is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 764 feet, Logan County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Irises during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Logan County, KS (Zone 6a) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Logan County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.4

Drainage

Well Drained

Irises Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Transplant: May 2 🌸 Bloom: Jun 27 – Jul 25
Recommended (50%) ✓ Fits season (74 days to spare)
Transplant: May 7 🌸 Bloom: Jul 2 – Jul 30
Safe Start (90%) ✓ Fits season (73 days to spare)
Transplant: May 20 🌸 Bloom: Jul 15 – Aug 12

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 Logan County

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

Soil pH

Your soil pH (6.3–7.4) overlaps with Irises's range (6.8–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Irises.

How to Plant Irises

0.5"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Irises

3
successive plantings in your 165-day season

Sow every 6.9 weeks. Last sowing by Jul 04 to harvest before frost.

Irises Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Irises

Irises needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Irises Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 2.4" 0" ✅ Rainfall sufficient
May 2.2" 2.9" 0" ✅ Rainfall sufficient
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 2.2" 1.8" 0.4" 💧 Light watering
Nov 1.8" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Irises 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.

Irises needs ~1,100 GDD — county provides 2,268 GDD Excellent fit

Irises Planting Timeline — Logan County, KS

Irises Planting Calendar

Activity When Date Range
Transplant Outdoors May 7 May 7 – May 21
Bloom July 2 Jul 2 – Jul 30

Plant 0.5" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6.8–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

165 days in Logan County

Growing Tips for Irises in Logan County

Direct sow Irises outdoors after April 30 in Logan County when soil has warmed and frost danger has passed.

Logan County receives only 22" of rain annually. Irises needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant rhizomes in late summer to early fall (July–September) after bloom season, setting them horizontally with the top of the rhizome at or just slightly below soil surface — never deeply buried. Full sun is essential for best bloom; at least 6 hours. Well-drained soil is critical; wet rhizomes rot in winter. After bloom, remove flower stalks but leave foliage until it browns in fall. Divide every 3–5 years in late summer when clumps become congested (crowded rhizomes stop blooming). Iris borer is the primary pest — remove and destroy affected fans. Year 2+ after division delivers the most bloom; freshly divided rhizomes may have limited or no bloom in their first season.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Irises in Logan County, KS?

Logan County is in Zone 6a with an average last frost of April 30. Plan your Irises planting based on this frost date — see the calendar above for exact timing.

What planting zone is Logan County, KS?

Logan County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 30 and first fall frost is October 12.

When should I plant Irises in Logan County, KS?

In Logan County, KS, plant Irises after the last frost (around April 30) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Logan County, KS for Irises?

Logan County sits in USDA Zone 6a. Irises grows reliably in zones 3a through 9b, so it's a good fit here.

Can Irises grow in Logan County's climate?

Yes — Irises grows well in Logan County's temperate climate. Logan County averages a 165-day frost-free season, with last frost around April 30 and first frost around October 12.

🌱

Your Logan County Garden Planner — Free

A 22-page printable planner built for Logan County (Zone 6a). 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 Logan County, KS. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.