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When to plant Bleeding Hearts in Flathead County, MT

Plant Bleeding Hearts in Flathead County, between June 17 and July 1 — the only viable window. Zone 5a's short season (99 frost-free days) rules out a fall crop.

When to Plant Bleeding Hearts in Flathead County, MT

Flathead County, Montana Zone 5a June

This month in 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.

Avg. last frost June 3
Avg. first frost September 10
Soil temp (4") 51°F
Watering High
Pest pressure High
Daylight 15.8 hrs

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Bleeding Hearts (Lamprocapnos spectabilis) are elegant woodland perennials producing arching stems hung with distinctive heart-shaped pink or white flowers with protruding inner petals — the "drops" beneath each heart. A beloved heirloom perennial from Asia, bleeding hearts emerge vigorously in spring, bloom prolifically for 4–6 weeks, and then go dormant in summer heat — a natural die-back that is entirely normal. The dormancy gap should be planned for by interplanting with summer-emerging hostas, ferns, or impatiens. Fringed bleeding heart (Dicentra eximia), a US native, has a longer bloom season and does not go fully dormant. All parts are toxic if ingested.

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 Bleeding Hearts during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Flathead County, MT (Zone 5a) Very short season
99 days
Last Spring Frost June 3
99 growing days
First Fall Frost September 10

Flathead County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Bleeding Hearts Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 20 Transplant: Jun 5 🌸 Bloom: Jul 31 – Sep 11
Recommended (50%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 17 🌸 Bloom: Aug 12 – Sep 23
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jul 6 🌸 Bloom: Aug 31 – Oct 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 Flathead County

How your county's soil matches Bleeding Hearts's growing requirements.

Soil pH

Your soil pH (6.6–8.4) is more alkaline than Bleeding Hearts prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Flathead County is excellent for Bleeding Hearts — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Bleeding Hearts.

How to Plant Bleeding Hearts

1.5"
Planting Depth
24"
Between Plants
30"
Between Rows

Bleeding Hearts Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 129 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Bleeding Hearts

Bleeding Hearts needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Bleeding Hearts 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.

Bleeding Hearts 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.

Bleeding Hearts needs ~1,144 GDD — county provides 1,509 GDD Excellent fit

Bleeding Hearts Planting Timeline — Flathead County, MT

Bleeding Hearts Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors June 17 Jun 17 – Jul 1
Bloom August 12 Aug 12 – Sep 23

Plant 1.5" deep · 24" apart · Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

99 days in Flathead County

Growing Tips for Bleeding Hearts in Flathead County

Direct sow Bleeding Hearts 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 Bleeding Hearts (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Flathead County receives only 21" of rain annually. Bleeding Hearts needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bare-root crowns in early spring as soon as soil is workable, or in fall at least 6 weeks before hard freeze. Set eyes 1–2 inches below soil level. Morning sun with afternoon shade is ideal; deep shade is tolerated but reduces bloom. Keep moist but well-drained — will not tolerate waterlogged soil. After flowering, the foliage will yellow and die back in summer heat — this is normal. Do not cut back until foliage turns fully yellow; the plant is storing energy. Mark the location to avoid disturbing crowns during summer dormancy. Divide every 4–5 years in early spring. Year 2+ plants produce the fullest flowering display.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bleeding Hearts in Flathead County, MT?

Flathead County is in Zone 5a with an average last frost of June 3. Plan your Bleeding Hearts 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 Bleeding Hearts in Flathead County, MT?

In Flathead County, MT, plant Bleeding Hearts 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, MT for Bleeding Hearts?

Flathead County sits in USDA Zone 5a. Bleeding Hearts grows reliably in zones 3a through 9a, so it's a good fit here.

Can Bleeding Hearts grow in Flathead County's climate?

Yes — Bleeding Hearts grows well in Flathead County's temperate climate. Flathead 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.

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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 Flathead County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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