When to plant Vinca (Annual) in Warren County, MO
Plant Vinca (Annual) in Warren County, between April 18 and May 2 — the only viable window. Zone 6b's short season (197 frost-free days) rules out a fall crop.
When to Plant Vinca (Annual) in Warren County, MO
June in the garden — Warren County, Missouri
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Warren County, Missouri.
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Start vinca (annual) under lights
These need a head start before your last frost (April 11). Sow into cells now so you're ready to transplant in a few weeks.
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Harvest vinca (annual) as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
A few tasks this June that'll pay off in July
- First harvests: vinca (annual)
Annual vinca (Catharanthus roseus), also called Madagascar periwinkle, is one of the most heat- and drought-tolerant bedding plants available. Glossy foliage stays attractive all season while cheerful pinwheel blooms continue without deadheading. A top performer in hot, humid Southern summers where impatiens and begonias struggle. Self-cleaning; requires little maintenance once established.
Warren County, Missouri is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.
At an elevation of 654 feet, Warren County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Vinca (Annual) during the growing season.
Warren County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.5
Drainage
Well Drained
Vinca (Annual) 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 Warren County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (5.5–6.5) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Warren County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Vinca (Annual).
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 27 to harvest before frost.
Vinca (Annual) Water Budget
Monthly Watering Guide for Vinca (Annual)
Vinca (Annual) 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 | Vinca (Annual) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Warren County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Vinca (Annual) 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.
Vinca (Annual) Planting Timeline — Warren County, MO
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 31 | Jan 31 – Feb 14 |
| Transplant Outdoors | April 18 | Apr 18 – May 2 |
| Bloom | June 27 | Jun 27 – Oct 10 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Warren County
Growing Tips for Vinca (Annual) in Warren County
Direct sow Vinca (Annual) outdoors after April 11 in Warren County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors 10–12 weeks before last frost — germination requires warm soil (75–80°F) and darkness. Do not cover seeds deeply; they need just a light dusting. Direct sowing is rarely practiced due to slow seedling establishment. Transplant after soil warms and frost danger has passed. Excellent drought tolerance once established; avoid overwatering. Performs best in well-drained beds or containers in full sun.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Vinca (Annual) in Other Locations
Frequently Asked Questions
When should I plant Vinca (Annual) in Warren County, MO?
Warren County is in Zone 6b with an average last frost of April 11. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Warren County, MO?
Warren County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 25.
When should I plant Vinca (Annual) in Warren County, MO?
In Warren County, MO, plant Vinca (Annual) after the last frost (around April 11) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Warren County, MO for Vinca (Annual)?
Warren County sits in USDA Zone 6b. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.
Can Vinca (Annual) grow in Warren County's climate?
Yes — Vinca (Annual) grows well in Warren County's temperate climate. Warren County averages a 197-day frost-free season, with last frost around April 11 and first frost around October 25.
Your Warren County Garden Planner — Free
A 22-page printable planner built for Warren 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.