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When to Plant Columbine in Multnomah County, OR

Multnomah County, Oregon Zone 9a June

Your June planting checklist for Multnomah County, Oregon

Your Multnomah County, Oregon garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 14
Avg. first frost October 27
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Get columbine seeds going inside

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Pick columbine

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

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Wild Columbine (Aquilegia canadensis) is a graceful native perennial of eastern North America, producing distinctive nodding flowers with spurred red-and-yellow petals that are irresistible to hummingbirds and native bees in spring. Its blue-green, fernlike foliage remains attractive long after flowering. Garden hybrid columbines (A. x hybrida) extend the color palette to the full spectrum and are equally adaptable. Short-lived by perennial standards (3–4 years per plant), but prolific self-seeders that perpetuate themselves and even hybridize freely in the garden, creating ever-evolving color combinations. An ideal woodland edge and cottage garden plant.

Multnomah County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Columbine to ensure they mature before fall.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Multnomah County, OR (Zone 9a) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Multnomah County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

Drainage

Well Drained

Columbine Planting Risk Windows

Early Start (70% safe) ✓ Fits season (137 days to spare)
Start indoors: Feb 11 Transplant: Mar 25 🌸 Bloom: May 13 – Jun 3
Recommended (50%) ✓ Fits season (140 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🌸 Bloom: May 19 – Jun 9
Safe Start (90%) ✓ Fits season (138 days to spare)
Start indoors: Mar 14 Transplant: Apr 25 🌸 Bloom: Jun 13 – Jul 4

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 Multnomah County

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

Soil pH

Your soil pH (5.8–6.3) overlaps with Columbine's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Columbine.

Organic Matter

Organic matter is excellent (4.5%) — Columbine will thrive.

How to Plant Columbine

0.1"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Columbine

3
successive plantings in your 196-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

Columbine Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 926 gal / 100 sq ft

Monthly Watering Guide for Columbine

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

Month Columbine Needs Rainfall You Supplement Action
Jan 5.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.3" 2.3" 2" 💧 Light watering
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 6" 0" ❄️ Dormant
Dec 4.9" 0" ❄️ Dormant

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

Columbine 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.

Columbine needs ~1,105 GDD — county provides 2,548 GDD Excellent fit

Columbine Planting Timeline — Multnomah County, OR

Columbine Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow March 31 Mar 31 – Apr 21
Bloom May 19 May 19 – Jun 9

Plant 0.1" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

196 days in Multnomah County

Growing Tips for Columbine in Multnomah County

Direct sow Columbine outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost with 4–6 weeks of cold moist stratification first (mix seeds with moist perlite in a bag and refrigerate), or direct-sow outdoors in fall for natural stratification. Transplant to the garden 2–4 weeks after last frost in spring. Prefers cool, moist, well-drained soil with morning sun and afternoon shade, especially in Zones 6+. After bloom, allow seed pods to mature and scatter if you want natural self-seeding; deadhead if you want to prevent spreading. Individual plants are typically short-lived (3–5 years) but colonies persist through prolific self-seeding. Leafminers may create white tunnels in foliage — unsightly but rarely serious. Year 2+ plants flower most profusely.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Columbine in Multnomah County, OR?

Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Columbine planting based on this frost date — see the calendar above for exact timing.

What planting zone is Multnomah County, OR?

Multnomah County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 27.

🌱

Your Multnomah County Garden Planner — Free

A 22-page printable planner built for Multnomah 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 Multnomah 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.