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When to Plant Coreopsis in Converse County, WY

Converse County, Wyoming Zone 5a June

June to-do list for Converse County, Wyoming

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

Avg. last frost June 4
Avg. first frost September 18
Soil temp (4") 47°F
Watering Critical
Pest pressure High
Daylight 15.2 hrs
  1. Move coreopsis from tray to bed

    Your last frost (June 4) has passed. These warm-season crops can handle outdoor soil now.

  2. Scatter coreopsis into prepared beds

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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Coreopsis (Tickseed) is a cheerful, long-blooming native perennial that produces a continuous flush of bright yellow, gold, or bi-colored daisy-like flowers from early summer well into fall. One of the most reliable cut-and-come-again bloomers in the perennial garden, it thrives in hot, dry, sunny conditions and poor soil where many competitors struggle. An invaluable nectar source for native bees and butterflies, and a butterfly host plant for several species.

Converse County, Wyoming is in USDA Zone 5a. The average last spring frost is June 4 and the first fall frost is September 18, giving you a growing season of approximately 106 days.

At an elevation of 6,089 feet, Converse County receives approximately 16.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Coreopsis to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Coreopsis successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Converse County, WY (Zone 5a) Short season
106 days
Last Spring Frost June 4
106 growing days
First Fall Frost September 18
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Converse County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 19 Transplant: Jun 4 🌸 Bloom: Aug 13 – Nov 19
Recommended (50%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 18 🌸 Bloom: Aug 27 – Dec 3
Safe Start (90%) ✗ May not fit
Start indoors: Apr 15 Transplant: Jul 1 🌸 Bloom: Sep 9 – Dec 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 Converse County

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

Soil pH

Your soil pH (6.6–8.3) overlaps with Coreopsis's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Coreopsis

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Coreopsis 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 Coreopsis

Coreopsis 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 Coreopsis Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 2.2" 1.2" 1" 💧 Light watering
Jul 2.2" 1.5" 0.7" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Coreopsis 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.

Coreopsis needs ~752 GDD — county provides 1,139 GDD Excellent fit

Coreopsis Planting Timeline — Converse County, WY

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 11 Jun 11 – Jul 2
Bloom August 27 Aug 27 – Dec 3

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

106 days in Converse County

Growing Tips for Coreopsis in Converse County

Direct sow Coreopsis outdoors after June 04 in Converse County when soil has warmed and frost danger has passed.

Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

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

General growing tips

Start seeds indoors 8–10 weeks before last frost or direct sow after last frost. Seeds germinate easily without stratification. Thrives in poor to average, well-drained soil — rich soil promotes foliage over flowers. Drought tolerant once established; overwatering is the most common mistake. Deadhead spent blooms to maintain continuous flowering through the season. Shear plants by one-third in midsummer for a fresh flush of late-season blooms. Year 2+ plants bloom most heavily. Divide every 2–3 years in early spring to rejuvenate crowded clumps.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Coreopsis in Converse County, WY?

Converse County is in Zone 5a with an average last frost of June 4. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Converse County, WY?

Converse County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is June 4 and first fall frost is September 18.

🌱

Your Converse County Garden Planner — Free

A 22-page printable planner built for Converse 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 Converse 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.