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When to Plant Pawpaw in Missoula County, MT

Missoula County, Montana Zone 5b May

Top priorities for Missoula County, Montana gardeners in May

May is a pivotal month for Missoula County, Montana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 14
Avg. first frost September 23
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: pawpaw

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Pawpaw is the largest native fruit tree in North America, producing tropical-tasting custard-like fruits. Young trees prefer shade but fruiting trees need good light.

Missoula County, Montana is in USDA Zone 5b. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.

At an elevation of 8,019 feet, Missoula County receives approximately 15.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Pawpaw during the growing season. With low rainfall, drip irrigation is essential for growing Pawpaw successfully. Mulch heavily to conserve soil moisture.

Missoula County, MT (Zone 5b) Short season
132 days
Last Spring Frost May 14
132 growing days
First Fall Frost September 23
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Missoula County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 29
Recommended (50%) ✓ Fits season
Transplant: Jun 4
Safe Start (90%) ✓ Fits season
Transplant: Jun 25

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 Missoula County

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

Soil pH

Your soil pH (6.2–7.7) overlaps with Pawpaw's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Pawpaw.

How to Plant Pawpaw

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 697 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Pawpaw

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

Month Pawpaw Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 4.3" 1.7" 2.6" 🚿 Regular watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Pawpaw 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.

Pawpaw needs ~27,831 GDD — county provides 2,013 GDD May not mature

Pawpaw Planting Timeline — Missoula County, MT

Pawpaw Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 – Jun 18

· 120" apart · Rows 144" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

1095–2555 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

132 days in Missoula County

Growing Tips for Pawpaw in Missoula County

Direct sow Pawpaw outdoors after May 14 in Missoula County when soil has warmed and frost danger has passed.

Your 132.0-day growing season in Missoula County is tight for Pawpaw (1095.0-2555.0 days to maturity). Start indoors and choose early-maturing varieties.

Missoula County receives only 16" of rain annually. Pawpaw needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant at least two genetically distinct trees for cross-pollination. Provide shade for young trees. Fruits ripen in fall and have a very short shelf life. Harvest when slightly soft.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pawpaw in Missoula County, MT?

Missoula County is in Zone 5b with an average last frost of May 14. Plan your Pawpaw planting based on this frost date — see the calendar above for exact timing.

What planting zone is Missoula County, MT?

Missoula County, Montana is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 23.

🌱

Your Missoula County Garden Planner — Free

A 24-page printable planner built for Missoula County (Zone 5b). 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 Missoula County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

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