When to plant Vinca (Annual) in Union County County,
In Union County County, Vinca (Annual) is a single-season spring crop — there's no second fall window. Plant April 11–April 25 for an 90-day harvest, finishing well before the October 23 first frost.
When to Plant Vinca (Annual) in Union County, GA
June in Union County, Georgia — your action list
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
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Begin indoor sowing: vinca (annual)
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Collect vinca (annual) at their peak
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
July prep starts now
- 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.
Union County, Georgia is in USDA Zone 7b. The average last spring frost is April 11 and the first fall frost is October 23, giving you a growing season of approximately 195 days.
At an elevation of 175 feet, Union County receives approximately 61.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, providing good warmth for Vinca (Annual) during the growing season. Clay soil retains moisture well for Vinca (Annual), but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.
Union County Soil Profile
Soil Type
Clay Loam
Soil pH
5.8-6.2
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 Union County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (5.8–6.2) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.
Soil Texture
The clay loam soil in Union County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Vinca (Annual).
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 25 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 | — | 6" | 0" | ❄️ Dormant |
| Feb | — | 4.6" | 0" | ❄️ Dormant |
| Mar | — | 5.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 5.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 6.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 4.2" | 0" | ❄️ Dormant |
| Dec | — | 5.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union 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 — Union County, GA
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 31 | Jan 31 – Feb 14 |
| Transplant Outdoors | April 11 | Apr 11 – Apr 25 |
| Bloom | June 20 | Jun 20 – Oct 24 |
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 | — |
| 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 7b
📆 Growing Season
195 days in Union County
Growing Tips for Vinca (Annual) in Union County
Direct sow Vinca (Annual) outdoors after April 11 in Union County when soil has warmed and frost danger has passed.
With Union County's clay soil (28% clay), work in 3-4 inches of compost before planting Vinca (Annual). Avoid tilling when soil is wet to prevent compaction.
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 Union County, GA?
Union County is in Zone 7b 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 Union County, GA?
Union County, Georgia is in USDA Hardiness Zone 7b. The average last spring frost is April 11 and first fall frost is October 23.
When should I plant Vinca (Annual) in Union County County, ?
In Union County County, , plant Vinca (Annual) after the last frost (around April 11) and before the first frost (around October 23). Best results when soil holds above 50°F.
What growing zone is Union County County, for Vinca (Annual)?
Union County County sits in USDA Zone 7b. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.
Can Vinca (Annual) grow in Union County County's climate?
Yes — Vinca (Annual) grows well in Union County County's temperate climate. Union County County averages a 195-day frost-free season, with last frost around April 11 and first frost around October 23.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.