When to Plant Valerian in Clark County, MO
What to do in May
Here's what deserves your attention in Clark County, Missouri this month. Everything below is tailored to Zone 6a and timed around your local frost dates.
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.
Clark County, Missouri is in USDA Zone 6a. The average last spring frost is April 16 and the first fall frost is October 18, giving you a growing season of approximately 185 days.
At an elevation of 833 feet, Clark County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Valerian during the growing season.
Clark County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.6
Drainage
Well Drained
Plant Planting Risk Windows
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 Clark County
How your county's soil matches Valerian's growing requirements.
Soil pH
Your soil pH (5.6–6.6) is within Valerian's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Clark County is excellent for Valerian — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Valerian.
How to Plant Valerian
Plant Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.3" | 1" | 💧 Light watering |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jul | 4.3" | 3.3" | 1" | 💧 Light watering |
| Aug | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Clark County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Valerian 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.
Valerian Planting Timeline — Clark County, MO
Valerian Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Harvest | August 27 | Aug 27 – Nov 5 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
120–180 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 6a
📆 Growing Season
185 days in Clark County
Growing Tips for Valerian in Clark County
Direct sow Valerian outdoors after April 16 in Clark County when soil has warmed and frost danger has passed.
Your 185.0-day growing season in Clark County is tight for Valerian (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
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 →
Valerian in Other Locations
Frequently Asked Questions
When should I plant Valerian in Clark County, MO?
Clark County is in Zone 6a with an average last frost of April 16. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, MO?
Clark County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 16 and first fall frost is October 18.
Your Clark County Garden Planner — Free
A 24-page printable planner built for Clark County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.