When to Plant Irises in Fillmore County, NE
Top priorities for Fillmore County, Nebraska gardeners in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Fillmore County, Nebraska.
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Bring in the irises
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
July prep starts now
- First harvests: irises
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.
Fillmore County, Nebraska is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 12, giving you a growing season of approximately 173 days.
At an elevation of 733 feet, Fillmore County receives approximately 33.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Irises to ensure they mature before fall.
Fillmore County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.4
Drainage
Well Drained
Irises Planting Risk Windows
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 Fillmore County
How your county's soil matches Irises's growing requirements.
Soil pH
Your soil pH (6.2–7.4) overlaps with Irises's range (6.8–7.0), though not a perfect match.
Soil Texture
The loam soil in Fillmore County is excellent for Irises — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Irises.
How to Plant Irises
Succession Planting Irises
Sow every 6.9 weeks. Last sowing by Jul 04 to harvest before frost.
Irises Water Budget
Water stress score is 6/10 — 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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Fillmore 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 Planting Timeline — Fillmore County, NE
Irises Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 29 | Apr 29 – May 13 |
| Bloom | June 24 | Jun 24 – Jul 22 |
Plant 0.5" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | Bloom |
| 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
173 days in Fillmore County
Growing Tips for Irises in Fillmore County
Direct sow Irises outdoors after April 22 in Fillmore County when soil has warmed and frost danger has passed.
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 →
Irises in Other Locations
Frequently Asked Questions
When should I plant Irises in Fillmore County, NE?
Fillmore County is in Zone 6a with an average last frost of April 22. Plan your Irises planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fillmore County, NE?
Fillmore County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 12.
Your Fillmore County Garden Planner — Free
A 22-page printable planner built for Fillmore 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.