When to plant Vinca (Annual) in Cumberland County, IL
Cumberland County's 186-day season only supports one Vinca (Annual) planting per year. Sow between April 21 and May 5 for the best chance at full maturity before October 17.
When to Plant Vinca (Annual) in Cumberland County, IL
Your July gardening checklist
If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.
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Harvest vinca (annual) as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
To set up a strong August, finish these tasks
- 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.
Cumberland County, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 772 feet, Cumberland County receives approximately 31.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Vinca (Annual) during the growing season.
Cumberland County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7
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 Cumberland County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (6.3–7.0) is within Vinca (Annual)'s preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Cumberland County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Vinca (Annual).
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 19 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cumberland 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 — Cumberland County, IL
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 3 | Feb 3 – Feb 17 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Bloom | June 30 | Jun 30 – Oct 13 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| 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: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
186 days in Cumberland County
Growing Tips for Vinca (Annual) in Cumberland County
Direct sow Vinca (Annual) outdoors after April 14 in Cumberland 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 Cumberland County, IL?
Cumberland County is in Zone 6b with an average last frost of April 14. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cumberland County, IL?
Cumberland County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 17.
When should I plant Vinca (Annual) in Cumberland County, IL?
In Cumberland County, IL, plant Vinca (Annual) after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Cumberland County, IL for Vinca (Annual)?
Cumberland 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 Cumberland County's climate?
Yes — Vinca (Annual) grows well in Cumberland County's temperate climate. Cumberland County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Cumberland County Garden Planner — Free
A 22-page printable planner built for Cumberland 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.