When to plant Lilies in Flathead County County,
Plant Lilies in Flathead County County during the brief June 17–July 1 window. With 99 frost-free days, fall plantings can't mature before September 10.
When to Plant Lilies in Flathead County, MT
Your June game plan for Flathead County, Montana
Your garden in Flathead County, Montana is working on a schedule, even when you're not. Here's where you should be this June.
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Get lilies in the ground
Frost risk is low now in Flathead County, Montana. If you've been covering beds overnight, you can stop.
Lilies (Lilium spp.) are among the most impressive summer-blooming bulbs, delivering bold, upward- or outward-facing trumpet blooms on tall stems from June through August. Asiatic hybrids are the most cold-hardy, earliest to bloom, and easiest to grow; Oriental hybrids bloom later with intensely fragrant, larger flowers. Orienpet (OT) hybrids combine the hardiness of Asiatics with the fragrance and size of Orientals. True lilies (not to be confused with daylilies, which are Hemerocallis) form scaly bulbs that persist and multiply underground, returning reliably each year with increasingly large clumps.
Flathead County, Montana is in USDA Zone 5a. The average last spring frost is June 3 and the first fall frost is September 10, giving you a growing season of approximately 99 days.
At an elevation of 6,233 feet, Flathead County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Lilies during the growing season.
Flathead County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.4
Drainage
Well Drained
Lilies 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 Flathead County
How your county's soil matches Lilies's growing requirements.
Soil pH
Your soil pH (6.6–8.4) is more alkaline than Lilies prefers (6.0–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Flathead County is excellent for Lilies — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Lilies.
How to Plant Lilies
Lilies Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Lilies
Lilies needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Lilies Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | — | 2.7" | 0" | ❄️ Dormant |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.6" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Flathead County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lilies 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.
Lilies Planting Timeline — Flathead County, MT
Lilies Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 17 | Jun 17 – Jul 1 |
| Bloom | August 26 | Aug 26 – Nov 18 |
Plant 5" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | Transplant Outdoors |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 6–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
99 days in Flathead County
Growing Tips for Lilies in Flathead County
Direct sow Lilies outdoors after June 03 in Flathead County when soil has warmed and frost danger has passed.
Your 99.0-day growing season in Flathead County is tight for Lilies (70.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
Flathead County receives only 21" of rain annually. Lilies needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Plant bulbs in fall (preferred, September–October) or spring, setting them 3 times their diameter deep (typically 4–6 inches) with the pointed end up. Lilies need excellent drainage — they will rot in wet or heavy clay soils. Site with full sun on stems and blooms but cool, shaded soil at the base (ground cover or shallow-rooted annuals at their feet is ideal). Remove spent blooms but leave stems and foliage until they yellow naturally, as the bulb needs the foliage to photosynthesize and rebuild energy stores. Red lily beetle is a serious pest in the Northeast and Pacific Northwest; inspect plants regularly and hand-pick adults and larvae. Never plant Oriental or Asiatic lilies near cats — all Lilium species are highly toxic to cats. Year 2+ bulbs produce the most stems and largest blooms.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Lilies in Other Locations
Frequently Asked Questions
When should I plant Lilies in Flathead County, MT?
Flathead County is in Zone 5a with an average last frost of June 3. Plan your Lilies planting based on this frost date — see the calendar above for exact timing.
What planting zone is Flathead County, MT?
Flathead County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 3 and first fall frost is September 10.
When should I plant Lilies in Flathead County County, ?
In Flathead County County, , plant Lilies after the last frost (around June 3) and before the first frost (around September 10). Best results when soil holds above 50°F.
What growing zone is Flathead County County, for Lilies?
Flathead County County sits in USDA Zone 5a. Lilies grows reliably in zones 3a through 9a, so it's a good fit here.
Can Lilies grow in Flathead County County's climate?
Yes — Lilies grows well in Flathead County County's temperate climate. Flathead County County averages a 99-day frost-free season, with last frost around June 3 and first frost around September 10.
Your Flathead County Garden Planner — Free
A 22-page printable planner built for Flathead County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.