When to plant Impatiens in Clark County, MO
In Clark County, Impatiens is a single-season spring crop — there's no second fall window. Plant April 23–May 7 for an 60–75-day harvest, finishing well before the October 18 first frost.
When to Plant Impatiens in Clark County, MO
What to do in June
June is a pivotal month for Clark County, Missouri gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Start impatiens under lights
Your window is short. These crops want several weeks of indoor growth before they go outside.
July prep starts now
- First harvests: impatiens
Impatiens (Impatiens walleriana) are the go-to annual for shaded beds and containers. They produce a continuous carpet of flat-faced blooms from transplant until frost, needing little deadheading. Their preference for consistent moisture and part-shade makes them ideal under trees and along north-facing borders.
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 Impatiens during the growing season.
Clark County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.6
Drainage
Well Drained
Impatiens 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 Impatiens's growing requirements.
Soil pH
Your soil pH (5.6–6.6) overlaps with Impatiens's range (6.0–6.5), though not a perfect match.
Soil Texture
The silt loam soil in Clark County is excellent for Impatiens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Impatiens.
How to Plant Impatiens
Succession Planting Impatiens
Sow every 6.9 weeks. Last sowing by Aug 04 to harvest before frost.
Impatiens Water Budget
Monthly Watering Guide for Impatiens
Impatiens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Impatiens 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.
Impatiens 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.
Impatiens Planting Timeline — Clark County, MO
Impatiens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 19 | Feb 19 – Mar 5 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Bloom | July 2 | Jul 2 – Oct 8 |
· 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–6.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
185 days in Clark County
Growing Tips for Impatiens in Clark County
Direct sow Impatiens outdoors after April 16 in Clark County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors 8–10 weeks before last frost at 70–75°F; germination requires light — do not cover seeds. Transplant after last frost once nights consistently exceed 50°F. Water regularly — wilting causes bud drop and they rarely fully recover the same flush. Watch for impatiens downy mildew (IDM); consider New Guinea impatiens as a resistant alternative in affected regions. Pinch tips at planting to encourage branching.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Impatiens in Other Locations
Frequently Asked Questions
When should I plant Impatiens in Clark County, MO?
Clark County is in Zone 6a with an average last frost of April 16. Plan your Impatiens 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.
When should I plant Impatiens in Clark County, MO?
In Clark County, MO, plant Impatiens after the last frost (around April 16) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Clark County, MO for Impatiens?
Clark County sits in USDA Zone 6a. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.
Can Impatiens grow in Clark County's climate?
Yes — Impatiens grows well in Clark County's temperate climate. Clark County averages a 185-day frost-free season, with last frost around April 16 and first frost around October 18.
Your Clark County Garden Planner — Free
A 22-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.