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When to Plant Valerian in Washington County, OK

Valerian is a tall perennial herb with fragrant white or pink flower clusters, valued for its root which is used as a natural sleep aid. It attracts pollinators and earthworms.

Washington County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 7 and the first fall frost is October 25, giving you a growing season of approximately 201 days.

At an elevation of 459 feet, Washington County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Valerian during the growing season.

Washington County, OK (Zone 7a) Long season
201 days
Last Spring Frost April 7
201 growing days
First Fall Frost October 25

Washington County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Monthly Watering Guide for Valerian

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

Month Valerian Needs Rainfall You Supplement Action
Jan 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 2.8" 1.5" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Valerian Planting Timeline — Washington County, OK

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors April 14 Apr 14 – Apr 28
Harvest August 18 Aug 18 – Nov 24

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May
June
July
August Harvest
September Harvest
October Harvest
November Harvest
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 7a

📆 Growing Season

201 days in Washington County

Growing Tips for Washington County

Start seeds indoors and transplant after last frost. Harvest roots in fall of the second year. Deadhead flowers unless you want self-seeding. Cats are attracted to valerian root.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Valerian in Washington County, OK?

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

What planting zone is Washington County, OK?

Washington County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 7 and first fall frost is October 25.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington 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.

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 Washington County, OK. 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.