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When to Plant Columbine in Spokane County, WA

Spokane County, Washington Zone 6b July

Top priorities for Spokane County, Washington gardeners in July

Here's what deserves your attention in Spokane County, Washington this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost May 11
Avg. first frost September 27
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 15.4 hrs
  1. Start columbine indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. It's harvest week for columbine

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

August prep starts now
  • First harvests: columbine

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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.

Spokane County, Washington is in USDA Zone 6b. The average last spring frost is May 11 and the first fall frost is September 27, giving you a growing season of approximately 139 days.

At an elevation of 1,645 feet, Spokane County receives approximately 20.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Columbine during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Spokane County, WA (Zone 6b) Short season
139 days
Last Spring Frost May 11
139 growing days
First Fall Frost September 27

Spokane County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Columbine Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Feb 26 Transplant: May 7 🌸 Bloom: Jul 2 – Aug 6
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 9 Transplant: May 18 🌸 Bloom: Jul 13 – Aug 17
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 10 Transplant: Jun 19 🌸 Bloom: Aug 14 – Sep 18

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 Spokane County

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

Soil pH

Your soil pH (5.5–6.2) is more acidic than Columbine prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.4%) — Columbine will thrive.

How to Plant Columbine

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

Succession Planting Columbine

2
successive plantings in your 139-day season

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

Columbine Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 475 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 3.1" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 4.3" 1.3" 3" 🚿 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" 0.7" 3.6" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 3.3" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Spokane 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 ~1,551 GDD — county provides 2,536 GDD Excellent fit

Columbine Planting Timeline — Spokane County, WA

Columbine Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 18 May 18 – Jun 8
Bloom July 13 Jul 13 – Aug 17

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Bloom
August Bloom
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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

139 days in Spokane County

Growing Tips for Columbine in Spokane County

Direct sow Columbine outdoors after May 11 in Spokane County when soil has warmed and frost danger has passed.

Spokane County receives only 20" of rain annually. Columbine 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 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 Spokane County, WA?

Spokane County is in Zone 6b with an average last frost of May 11. Plan your Columbine planting based on this frost date — see the calendar above for exact timing.

What planting zone is Spokane County, WA?

Spokane County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 11 and first fall frost is September 27.

🌱

Your Spokane County Garden Planner — Free

A 22-page printable planner built for Spokane County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Spokane County, WA. Local conditions may vary. Last updated: July 2026.

Sources & credits

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