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When to plant Coreopsis in La Plata County, CO

Plant Coreopsis in La Plata County during the brief June 7–June 28 window. With 113 frost-free days, fall plantings can't mature before September 21.

When to Plant Coreopsis in La Plata County, CO

La Plata County, Colorado Zone 6a June

This month in La Plata County, Colorado

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in La Plata County, Colorado.

Avg. last frost May 31
Avg. first frost September 21
Soil temp (4") 54°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Time to transplant coreopsis

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Scatter coreopsis into prepared beds

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

La Plata County, Colorado is in USDA Zone 6a. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 5,246 feet, La Plata County receives approximately 14.9 inches of rainfall annually with predominantly loam soil. Summer highs average 83°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
La Plata County, CO (Zone 6a) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21

La Plata County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.9

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 12 Transplant: May 21 🌸 Bloom: Jul 30 – Nov 19
Recommended (50%) ✗ May not fit
Start indoors: Mar 29 Transplant: Jun 7 🌸 Bloom: Aug 16 – Dec 6
Safe Start (90%) ✓ Fits season (284 days to spare)
Start indoors: Apr 24 Transplant: Jul 3 🌸 Bloom: Sep 11 – Jan 1

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 La Plata County

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

Soil pH

Your soil pH (6.2–7.9) overlaps with Coreopsis's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in La Plata 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

Succession Planting Coreopsis

2
successive plantings in your 113-day season

Sow every 6.9 weeks. Last sowing by Jul 03 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 0.9" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.6" 0.6" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 1.4" 0.8" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light 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 La Plata 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 ~858 GDD — county provides 1,384 GDD Excellent fit

Coreopsis Planting Timeline — La Plata County, CO

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors June 7 Jun 7 – Jun 21
Direct Sow June 7 Jun 7 – Jun 28
Bloom August 16 Aug 16 – Dec 6

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

Month-by-Month Timeline

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

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 6a

📆 Growing Season

113 days in La Plata County

Growing Tips for Coreopsis in La Plata County

Direct sow Coreopsis outdoors after May 31 in La Plata 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.

La Plata County receives only 15" 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 La Plata County, CO?

La Plata County is in Zone 6a with an average last frost of May 31. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is La Plata County, CO?

La Plata County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 31 and first fall frost is September 21.

When should I plant Coreopsis in La Plata County, CO?

In La Plata County, CO, plant Coreopsis after the last frost (around May 31) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is La Plata County, CO for Coreopsis?

La Plata County sits in USDA Zone 6a. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.

Can Coreopsis grow in La Plata County's climate?

Yes — Coreopsis grows well in La Plata County's temperate climate. La Plata County averages a 113-day frost-free season, with last frost around May 31 and first frost around September 21.

🌱

Your La Plata County Garden Planner — Free

A 22-page printable planner built for La Plata County (Zone 6a). 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 La Plata County, CO. 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.