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When to Plant Daffodils in Devils Tower, WY

Crook County, Wyoming Zone 4b July

This month in Crook County, Wyoming

We've pulled the most time-sensitive tasks for Crook County, Wyoming this July and put them front and centre. Tackle them in order.

Avg. last frost May 14
Avg. first frost October 1
Soil temp (4") 47°F
Watering High
Pest pressure High
Daylight 15 hrs
August prep starts now
  • Fall sowing: daffodils

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Daffodils (Narcissus spp.) are among the most dependable and longest-lived of all spring bulbs. Their cheerful yellow and white blooms emerge in early spring, often while frost is still possible, bringing color weeks before most other flowers. Unlike tulips, established clumps naturalize readily — spreading and returning reliably year after year without replanting. Deer and rodents avoid them due to toxic alkaloids in the bulb and sap, making them a low-maintenance choice for naturalized areas, woodland edges, and mixed borders.

Devils Tower, Wyoming is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is October 1, giving you a growing season of approximately 140 days.

At an elevation of 8,060 feet, Crook County receives approximately 24.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Daffodils to ensure they mature before fall.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Devils Tower, WY (Zone 4b) Short season
140 days
Last Spring Frost May 14
140 growing days
First Fall Frost October 1

Devils Tower Soil Profile

Soil Type

Loam

Soil pH

6.3-7.9

Drainage

Well Drained

Daffodils Planting Risk Windows

Early Start (70% safe) ✓ Fits season (154 days to spare)
Transplant: May 9 🌸 Bloom: Mar 21 – Apr 18
Recommended (50%) ✓ Fits season (161 days to spare)
Transplant: May 14 🌸 Bloom: Mar 26 – Apr 23
Safe Start (90%) ✓ Fits season (160 days to spare)
Transplant: May 29 🌸 Bloom: Apr 10 – May 8

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 Devils Tower

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

Soil pH

Your soil pH (6.3–7.9) is more alkaline than Daffodils prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Daffodils

7"
Planting Depth
7"
Between Plants
8"
Between Rows

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

Succession Planting Daffodils

8
successive plantings in your 140-day season

Sow every 2.3 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

Daffodils Water Budget

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

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

Monthly Watering Guide for Daffodils

Daffodils 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 Daffodils Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.2" 3.1" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 1.6" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Daffodils 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.

Daffodils needs ~345 GDD — county provides 1,610 GDD Excellent fit

Daffodils Planting Timeline — Devils Tower, WY

Daffodils Planting Calendar

Activity When Date Range
Bloom July 2 Jul 2 – Jul 30
Fall Sowing August 20 Aug 20 – Sep 3

Plant 7" deep · 7" apart · Rows 8" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

20–40 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

140 days in Crook County

Growing Tips for Daffodils in Devils Tower

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

Your generous 140.0-day season in Crook County allows multiple plantings of Daffodils. Sow every 10.0 days for continuous harvest.

Common pests for Daffodils in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

Crook County receives only 25" of rain annually. Daffodils needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bulbs pointed-end up in fall, 6–8 inches deep and 6–8 inches apart in well-drained soil. Allow 12–16 weeks of cold dormancy for proper vernalization. Do not cut back foliage until it turns yellow (6–8 weeks after bloom) — the dying leaves photosynthesize energy into the bulb for next year. Lift and divide overcrowded clumps every 4–5 years in summer after foliage dies back. In zones 7b–9b, select heat-tolerant cultivars (Jonquilla, Tazetta, and Cyclamineus divisions) that perform better with less chill than large-cupped types. Zones 10+: insufficient winter cold; pre-chilling is required but results inconsistent — not recommended for outdoor culture.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌱

Your Crook County Garden Planner — Free

A 22-page printable planner built for Crook 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.

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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 Crook County, WY. Local conditions may vary. Last updated: July 2026.