When to plant Impatiens in Cass County, MO
Cass County's short 191-day growing season means one Impatiens planting between April 21 and May 5. No fall crop in Zone 6b.
When to Plant Impatiens in Cass County, MO
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.
Cass County, Missouri is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 22, giving you a growing season of approximately 191 days.
At an elevation of 910 feet, Cass County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Impatiens during the growing season.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
Drainage
Well Drained
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| May | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Aug | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Sep | 4.3" | 3.3" | 1" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cass County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Impatiens Planting Timeline — Cass County, MO
Impatiens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 17 | Feb 17 – Mar 3 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Bloom | June 30 | Jun 30 – Oct 13 |
· 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 | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–6.5 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
191 days in Cass County
Growing Tips for Cass County
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 Cass County, MO?
Cass County is in Zone 6b with an average last frost of April 14. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, MO?
Cass County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 22.
When should I plant Impatiens in Cass County, MO?
In Cass County, MO, plant Impatiens after the last frost (around April 14) and before the first frost (around October 22). Best results when soil holds above 50°F.
What growing zone is Cass County, MO for Impatiens?
Cass County sits in USDA Zone 6b. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.
Can Impatiens grow in Cass County's climate?
Yes — Impatiens grows well in Cass County's temperate climate. Cass County averages a 191-day frost-free season, with last frost around April 14 and first frost around October 22.
Your Cass County Garden Planner — Free
A 22-page printable planner built for Cass 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.