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When to Plant Impatiens in Coos County, OR

Coos County, Oregon Zone 9a June

June in Coos County, Oregon — your action list

Here's what deserves your attention in Coos County, Oregon this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost March 22
Avg. first frost November 19
Soil temp (4") 81°F
Watering High
Pest pressure High
Daylight 15.2 hrs
  1. Pick impatiens

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to July
  • First harvests: 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.

Coos County, Oregon is in USDA Zone 9a. The average last spring frost is March 22 and the first fall frost is November 19, giving you a growing season of approximately 242 days.

At an elevation of 96 feet, Coos County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Impatiens during the growing season.

Annual Blooms in Summer Pollinator-friendly
Coos County, OR (Zone 9a) Long season
242 days
Last Spring Frost March 22
242 growing days
First Fall Frost November 19

Coos County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Impatiens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Jan 10 Transplant: Feb 21 🌸 Bloom: May 2 – Oct 17
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Jan 25 Transplant: Mar 8 🌸 Bloom: May 17 – Nov 1
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Feb 25 Transplant: Apr 8 🌸 Bloom: Jun 17 – Dec 2

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 Coos County

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

Soil pH

Your soil pH (5.4–6.8) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.7%) — Impatiens will thrive.

How to Plant Impatiens

10"
Between Plants
12"
Between Rows

Succession Planting Impatiens

4
successive plantings in your 242-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

Impatiens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 703 gal / 100 sq ft

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 5.5" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 4.3" 5.9" 0" ✅ Rainfall sufficient
Dec 5.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Coos 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 ~1,131 GDD — county provides 4,053 GDD Excellent fit

Impatiens Planting Timeline — Coos County, OR

Impatiens Planting Calendar

Activity When Date Range
Start Indoors January 25 Jan 25 – Feb 8
Transplant Outdoors March 8 Mar 8 – Mar 22
Bloom May 17 May 17 – Nov 1

· 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

242 days in Coos County

Growing Tips for Impatiens in Coos County

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

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 Coos County, OR?

Coos County is in Zone 9a with an average last frost of March 22. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coos County, OR?

Coos County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is March 22 and first fall frost is November 19.

🌱

Your Coos County Garden Planner — Free

A 22-page printable planner built for Coos County (Zone 9a). 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 Coos County, OR. 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.