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When to Plant Vinca (Annual) in Clatsop County, OR

Clatsop County, Oregon Zone 9a June

June in Clatsop County, Oregon — your action list

Each item below is timed to Clatsop County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 12
Avg. first frost November 4
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Fire up the seed-starting tray: vinca (annual)

    You're about 20 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. It's harvest week for vinca (annual)

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of July
  • First harvests: vinca (annual)

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Annual vinca (Catharanthus roseus), also called Madagascar periwinkle, is one of the most heat- and drought-tolerant bedding plants available. Glossy foliage stays attractive all season while cheerful pinwheel blooms continue without deadheading. A top performer in hot, humid Southern summers where impatiens and begonias struggle. Self-cleaning; requires little maintenance once established.

Clatsop County, Oregon is in USDA Zone 9a. The average last spring frost is April 12 and the first fall frost is November 4, giving you a growing season of approximately 206 days.

At an elevation of 412 feet, Clatsop County receives approximately 54.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Vinca (Annual) during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Clatsop County, OR (Zone 9a) Long season
206 days
Last Spring Frost April 12
206 growing days
First Fall Frost November 4

Clatsop County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Jan 21 Transplant: Mar 11 🌸 Bloom: May 20 – Nov 18
Recommended (50%) ✗ May not fit
Start indoors: Feb 1 Transplant: Mar 22 🌸 Bloom: May 31 – Nov 29
Safe Start (90%) ✗ May not fit
Start indoors: Feb 19 Transplant: Apr 9 🌸 Bloom: Jun 18 – Dec 17

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 Clatsop County

How your county's soil matches Vinca (Annual)'s growing requirements.

Soil pH

Your soil pH (5.6–6.7) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Clatsop County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) — Vinca (Annual) will thrive.

How to Plant Vinca (Annual)

0.1"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Vinca (Annual)

3
successive plantings in your 206-day season

Sow every 8 weeks. Last sowing by Aug 06 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Vinca (Annual)

Vinca (Annual) 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 Vinca (Annual) Needs Rainfall You Supplement Action
Jan 8.4" 0" ❄️ Dormant
Feb 5.2" 0" ❄️ Dormant
Mar 4.8" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 2.1" 0.1" 💧 Light watering
Jul 2.2" 0.9" 1.3" 🚿 Regular watering
Aug 2.2" 1.1" 1.1" 🚿 Regular watering
Sep 2.2" 2.4" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 8.4" 0" ✅ Rainfall sufficient
Dec 9.3" 0" ❄️ Dormant

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

Vinca (Annual) 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.

Vinca (Annual) needs ~1,160 GDD — county provides 2,987 GDD Excellent fit

Vinca (Annual) Planting Timeline — Clatsop County, OR

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 – Feb 15
Transplant Outdoors March 22 Mar 22 – Apr 5
Bloom May 31 May 31 – Nov 29

Plant 0.1" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

206 days in Clatsop County

Growing Tips for Vinca (Annual) in Clatsop County

Direct sow Vinca (Annual) outdoors after April 12 in Clatsop County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 10–12 weeks before last frost — germination requires warm soil (75–80°F) and darkness. Do not cover seeds deeply; they need just a light dusting. Direct sowing is rarely practiced due to slow seedling establishment. Transplant after soil warms and frost danger has passed. Excellent drought tolerance once established; avoid overwatering. Performs best in well-drained beds or containers in full sun.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Vinca (Annual) in Clatsop County, OR?

Clatsop County is in Zone 9a with an average last frost of April 12. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clatsop County, OR?

Clatsop County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 12 and first fall frost is November 4.

🌱

Your Clatsop County Garden Planner — Free

A 22-page printable planner built for Clatsop 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 Clatsop 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.