Blog

When to Plant Angelica in Rosebud County, MT

Rosebud County, Montana Zone 4b May

What to do in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 11
Avg. first frost October 3
Soil temp (4") 37°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Set out angelica seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Direct-sow angelica

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Before June arrives, get these ready
  • Starting indoors: angelica

Instant PDF download. No spam, unsubscribe any time.

Angelica is a dramatic biennial herb that can reach 6 feet tall with large compound leaves and globe-shaped flower clusters. All parts are edible with a sweet, celery-like flavor.

Rosebud County, Montana is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 3, giving you a growing season of approximately 145 days.

At an elevation of 6,448 feet, Rosebud County receives approximately 22.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Angelica to ensure they mature before fall.

Rosebud County, MT (Zone 4b) Short season
145 days
Last Spring Frost May 11
145 growing days
First Fall Frost October 3
Share this guide:

Rosebud County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Start indoors: Mar 24 Transplant: Apr 28
Recommended (50%) ✓ Fits season
Start indoors: Mar 30 Transplant: May 4
Safe Start (90%) ✓ Fits season
Start indoors: Apr 11 Transplant: May 16

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 Rosebud County

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

Soil pH

Your soil pH (6.4–7.8) is more alkaline than Angelica prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Angelica.

How to Plant Angelica

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,300 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Angelica

Angelica needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Angelica Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 6.5" 2.9" 3.6" 🚿 Regular watering
Jun 6.5" 1.7" 4.8" 🚿 Regular watering
Jul 6.5" 2" 4.5" 🚿 Regular watering
Aug 6.5" 2.1" 4.4" 🚿 Regular watering
Sep 6.5" 1.7" 4.8" 🚿 Regular watering
Oct 6.5" 1.8" 4.7" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Angelica 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.

Angelica needs ~7,118 GDD — county provides 1,885 GDD May not mature

Angelica Planting Timeline — Rosebud County, MT

Angelica Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 4 May 4 – May 18
Direct Sow May 4 May 4 – May 25
Fall Sowing July 11 Jul 11 – Jul 25

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Fall Sowing
August
September
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

145 days in Rosebud County

Growing Tips for Angelica in Rosebud County

Direct sow Angelica outdoors after May 11 in Rosebud County when soil has warmed and frost danger has passed.

Your 145.0-day growing season in Rosebud County is tight for Angelica (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Angelica in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

Rosebud County receives only 23" of rain annually. Angelica needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Sow fresh seeds in fall for spring germination. Provide rich, moist soil and partial shade. Harvest stems in the second year before flowering for candying or flavoring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Angelica in Rosebud County, MT?

Rosebud County is in Zone 4b with an average last frost of May 11. Plan your Angelica planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rosebud County, MT?

Rosebud County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 3.

🌱

Your Rosebud County Garden Planner — Free

A 24-page printable planner built for Rosebud County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rosebud 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.