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When to Plant Larkspur in Wheeler County, OR

Wheeler County, Oregon Zone 7a June

What to do in June

Welcome to June in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 23
Avg. first frost September 23
Soil temp (4") 65°F
Watering Critical
Pest pressure High
Daylight 15.4 hrs
Coming up in July — start thinking about
  • First harvests: larkspur
  • Fall sowing: larkspur

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Larkspur (Consolida ajacis) is a cool-season annual that produces tall, delicate spires of blue, purple, pink, and white flowers reminiscent of its perennial cousin, delphinium. Direct-sown into cold soil or fall-sown in mild-winter climates, it blooms in spring before going to seed as summer heat arrives. An excellent cut flower and cottage-garden staple.

Wheeler County, Oregon is in USDA Zone 7a. The average last spring frost is May 23 and the first fall frost is September 23, giving you a growing season of approximately 123 days.

At an elevation of 2,175 feet, Wheeler County receives approximately 22.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Larkspur to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Wheeler County, OR (Zone 7a) Short season
123 days
Last Spring Frost May 23
123 growing days
First Fall Frost September 23

Wheeler County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.3

Drainage

Well Drained

Larkspur Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 16 🌸 Bloom: Jul 25 – Oct 3
Recommended (50%) ✗ May not fit
Transplant: May 23 🌸 Bloom: Aug 1 – Oct 10
Safe Start (90%) ✗ May not fit
Transplant: Jun 19 🌸 Bloom: Aug 28 – Nov 6

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 Wheeler County

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

Soil pH

Your soil pH (5.2–6.3) is more acidic than Larkspur prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

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

How to Plant Larkspur

0.1"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Larkspur

2
successive plantings in your 123-day season

Sow every 6.9 weeks. Last sowing by Jun 25 to harvest before frost.

For a dedicated fall crop, sow by Jul 15.

Larkspur Water Budget

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

Monthly Watering Guide for Larkspur

Larkspur 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 Larkspur Needs Rainfall You Supplement Action
Jan 3" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.5" 0.7" 💧 Light watering
Jun 2.2" 1" 1.2" 🚿 Regular watering
Jul 2.2" 0.4" 1.8" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 3.3" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

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

Larkspur 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.

Larkspur needs ~919 GDD — county provides 1,506 GDD Excellent fit

Larkspur Planting Timeline — Wheeler County, OR

Larkspur Planting Calendar

Activity When Date Range
Direct Sow April 25 Apr 25 – May 16
Bloom July 4 Jul 4 – Sep 12
Fall Sowing July 15 Jul 15 – Jul 29

Plant 0.1" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Direct Sow
June
July Fall Sowing Bloom
August Bloom
September Bloom
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

123 days in Wheeler County

Growing Tips for Larkspur in Wheeler County

Direct sow Larkspur outdoors after May 23 in Wheeler County when soil has warmed and frost danger has passed.

Wheeler County receives only 23" of rain annually. Larkspur needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Larkspur does not transplant well — direct-sow only. In cold climates (zones 2–6), sow directly in early spring as soon as soil can be worked, 4–6 weeks before last frost; cold soil improves germination. In zones 7–10, fall-sow 8–10 weeks before first frost for spring bloom. Press seeds lightly into soil; they need darkness to germinate — cover with 1/8–1/4 inch of soil. Thin to 6–12 inches to prevent powdery mildew. Allow seed pods to mature and self-sow for naturalized colonies. All parts are toxic if ingested.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Larkspur in Wheeler County, OR?

Wheeler County is in Zone 7a with an average last frost of May 23. Plan your Larkspur planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wheeler County, OR?

Wheeler County, Oregon is in USDA Hardiness Zone 7a. The average last spring frost is May 23 and first fall frost is September 23.

🌱

Your Wheeler County Garden Planner — Free

A 22-page printable planner built for Wheeler 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 Wheeler 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.