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When to Plant Impatiens in Kittitas County, WA

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.

Kittitas County, Washington is in USDA Zone 7a. The average last spring frost is May 7 and the first fall frost is October 2, giving you a growing season of approximately 148 days.

At an elevation of 2,468 feet, Kittitas County receives approximately 18.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Impatiens during the growing season. With low rainfall, drip irrigation is essential for growing Impatiens successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly
Kittitas County, WA (Zone 7a) Short season
148 days
Last Spring Frost May 7
148 growing days
First Fall Frost October 2

Kittitas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

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 2.9" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 4.3" 1.2" 3.1" 🚿 Regular watering
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.8" 3.5" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

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

Impatiens Planting Timeline — Kittitas County, WA

Impatiens Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors May 14 May 14 – May 28
Bloom July 23 Jul 23 – Nov 12

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: N/A

🗺️ USDA Zone

Zone 7a

📆 Growing Season

148 days in Kittitas County

Growing Tips for Kittitas County

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 Kittitas County, WA?

Kittitas County is in Zone 7a with an average last frost of May 7. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kittitas County, WA?

Kittitas County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 7 and first fall frost is October 2.

🌱

Your Kittitas County Garden Planner — Free

A 22-page printable planner built for Kittitas County (Zone 7a). 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 Kittitas County, WA. Local conditions may vary. Last updated: August 2026.

Sources & credits

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