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When to plant Irises in Maries County, MO

Plant Irises in Maries County, between April 13 and April 27 — the only viable window. Zone 6b's short season (207 frost-free days) rules out a fall crop.

When to Plant Irises in Maries County, MO

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.

Maries County, Missouri is in USDA Zone 6b. The average last spring frost is April 6 and the first fall frost is October 30, giving you a growing season of approximately 207 days.

At an elevation of 684 feet, Maries County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Irises during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Maries County, MO (Zone 6b) Long season
207 days
Last Spring Frost April 6
207 growing days
First Fall Frost October 30

Maries County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Irises Planting Timeline — Maries County, MO

Irises Planting Calendar

Activity When Date Range
Transplant Outdoors April 13 Apr 13 – Apr 27
Bloom June 8 Jun 8 – Jul 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6.8–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

207 days in Maries County

Growing Tips for Maries County

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 Maries County, MO?

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

What planting zone is Maries County, MO?

Maries County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 6 and first fall frost is October 30.

When should I plant Irises in Maries County, MO?

In Maries County, MO, plant Irises after the last frost (around April 6) and before the first frost (around October 30). Best results when soil holds above 50°F.

What growing zone is Maries County, MO for Irises?

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

Can Irises grow in Maries County's climate?

Yes — Irises grows well in Maries County's temperate climate. Maries County averages a 207-day frost-free season, with last frost around April 6 and first frost around October 30.

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Your Maries County Garden Planner — Free

A 22-page printable planner built for Maries 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 Maries County, MO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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