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When to Plant Impatiens in Sublette County, WY

Sublette County, Wyoming Zone 4b June

Sublette County, Wyoming gardeners: here's your June plan

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

Avg. last frost June 22
Avg. first frost August 24
Soil temp (4") 47°F
Watering High
Pest pressure Moderate
Daylight 15.1 hrs
July prep starts now
  • Transplants going out: impatiens

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Impatiens (Impatiens walleriana) are the go-to annual for shaded beds and containers. They produce a continuous carpet of flat-faced blooms from transplant until frost, needing little deadheading. Their preference for consistent moisture and part-shade makes them ideal under trees and along north-facing borders.

Sublette County, Wyoming is in USDA Zone 4b. The average last spring frost is June 22 and the first fall frost is August 24, giving you a growing season of approximately 63 days.

At an elevation of 5,005 feet, Sublette County receives approximately 22.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Impatiens to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly
Sublette County, WY (Zone 4b) Very short season
63 days
Last Spring Frost June 22
63 growing days
First Fall Frost August 24

Sublette County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 15 Transplant: Jul 1 🌸 Bloom: Sep 16 – Nov 18
Recommended (50%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jul 6 🌸 Bloom: Sep 21 – Nov 23
Safe Start (90%) ✗ May not fit
Start indoors: Apr 28 Transplant: Jul 14 🌸 Bloom: Sep 29 – Dec 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 Sublette County

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

Soil pH

Your soil pH (6.7–7.8) is more alkaline than Impatiens prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Impatiens.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
1.5″/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 Impatiens

Impatiens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Impatiens Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 1.7" 0" ❄️ Dormant
Oct 2" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Impatiens 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.

Impatiens needs ~726 GDD — county provides 677 GDD Tight fit

Impatiens Planting Timeline — Sublette County, WY

Impatiens Planting Calendar

Activity When Date Range
Start Indoors April 20 Apr 20 – May 4
Transplant Outdoors July 6 Jul 6 – Jul 20
Bloom September 21 Sep 21 – Nov 23

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

63 days in Sublette County

Growing Tips for Impatiens in Sublette County

Direct sow Impatiens outdoors after June 22 in Sublette County when soil has warmed and frost danger has passed.

Your 63.0-day growing season in Sublette County is tight for Impatiens (60.0-75.0 days to maturity). Start indoors and choose early-maturing varieties.

Sublette County receives only 23" of rain annually. Impatiens 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 at 70–75°F; germination requires light — do not cover seeds. Transplant after last frost once nights consistently exceed 50°F. Water regularly — wilting causes bud drop and they rarely fully recover the same flush. Watch for impatiens downy mildew (IDM); consider New Guinea impatiens as a resistant alternative in affected regions. Pinch tips at planting to encourage branching.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Impatiens in Sublette County, WY?

Sublette County is in Zone 4b with an average last frost of June 22. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sublette County, WY?

Sublette County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is June 22 and first fall frost is August 24.

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Your Sublette County Garden Planner — Free

A 22-page printable planner built for Sublette 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 Sublette 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.