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When to Plant Crocus in Campbell County, WY

Campbell County, Wyoming Zone 5a June

This month in Campbell County, Wyoming

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

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 38°F
Watering High
Pest pressure High
Daylight 15.3 hrs

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Crocuses (Crocus spp.) are the heralds of spring — small, gem-like blooms that push up through frozen ground or even snow, often weeks before any other flower. Their compact corms naturalize readily in lawns, rock gardens, and borders, creating drifts of purple, white, and yellow that expand year after year. Bees prize early crocus as one of their first nectar and pollen sources of the season. The saffron crocus (C. sativus) blooms in fall and yields the world's most expensive spice.

Campbell County, Wyoming is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 8,132 feet, Campbell County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Crocus to ensure they mature before fall.

Bulb Blooms in Spring Pollinator-friendly Fragrant
Campbell County, WY (Zone 5a) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20

Campbell County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Crocus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (151 days to spare)
Transplant: May 14 🌸 Bloom: Mar 26 – Apr 16
Recommended (50%) ✓ Fits season (151 days to spare)
Transplant: May 20 🌸 Bloom: Apr 1 – Apr 22
Safe Start (90%) ✓ Fits season (148 days to spare)
Transplant: Jun 7 🌸 Bloom: Apr 19 – May 10

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 Campbell County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Crocus prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Crocus.

How to Plant Crocus

4"
Planting Depth
3"
Between Plants
4"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Crocus

15
successive plantings in your 123-day season

Sow every 1.1 weeks. Last sowing by Aug 31 to harvest before frost.

For a dedicated fall crop, sow by Aug 09.

Crocus Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Crocus

Crocus 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 Crocus Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 2.2" 2.7" 0" ✅ Rainfall sufficient
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.4" 0" ✅ Rainfall sufficient
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Crocus 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.

Crocus needs ~184 GDD — county provides 1,506 GDD Excellent fit

Crocus Planting Timeline — Campbell County, WY

Crocus Planting Calendar

Activity When Date Range
Bloom June 21 Jun 21 – Jul 12
Fall Sowing August 9 Aug 9 – Aug 23

Plant 4" deep · 3" apart · Rows 4" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Bloom
July Bloom
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

10–20 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Campbell County

Growing Tips for Crocus in Campbell County

Direct sow Crocus outdoors after May 20 in Campbell County when soil has warmed and frost danger has passed.

Your generous 123.0-day season in Campbell County allows multiple plantings of Crocus. Sow every 5.0 days for continuous harvest.

Campbell County receives only 22" of rain annually. Crocus needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant corms 3–4 inches deep and 2–3 inches apart in fall, when soil temperature drops below 60°F. Mass plantings (at least 25 corms per cluster) create the most visual impact. Plant in well-drained soil — corms rot in standing water. Crocus naturalize well under deciduous trees; the tree leafs out after crocus dormancy begins, so light competition is minimal. Squirrels and chipmunks dig corms — plant deeper (4 inches) or use wire mesh baskets in high-predation areas. Allow foliage to die back naturally before mowing lawns. In zones 8a–8b, plant in December with pre-chilled corms for best results.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Crocus in Campbell County, WY?

Campbell County is in Zone 5a with an average last frost of May 20. Plan your Crocus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Campbell County, WY?

Campbell County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 20.

🌱

Your Campbell County Garden Planner — Free

A 22-page printable planner built for Campbell 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 Campbell County, WY. Local conditions may vary. Last updated: June 2026.

Sources & credits

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