When to Plant Vinca (Annual) in Edwards County, TX
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.
Edwards County, Texas is in USDA Zone 8b. The average last spring frost is April 2 and the first fall frost is November 8, giving you a growing season of approximately 220 days.
At an elevation of 4,265 feet, Edwards County receives approximately 61.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°F, so Vinca (Annual) may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Vinca (Annual) will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.
Edwards County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.8-8.1
Drainage
Well Drained
Monthly Watering Guide for Vinca (Annual)
Vinca (Annual) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Vinca (Annual) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.5" | 0" | ❄️ Dormant |
| Feb | — | 3.3" | 0" | ❄️ Dormant |
| Mar | — | 3.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| May | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jun | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Jul | 4.3" | 11.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 13.8" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Dec | — | 4.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Edwards County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Vinca (Annual) Planting Timeline — Edwards County, TX
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 22 | Jan 22 – Feb 5 |
| Transplant Outdoors | March 19 | Mar 19 – Apr 2 |
| Bloom | May 28 | May 28 – Oct 29 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors |
| March | Transplant Outdoors |
| April | Transplant Outdoors |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 8b
📆 Growing Season
220 days in Edwards County
Growing Tips for Edwards County
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 Edwards County, TX?
Edwards County is in Zone 8b with an average last frost of April 2. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Edwards County, TX?
Edwards County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is April 2 and first fall frost is November 8.
Your Edwards County Garden Planner — Free
A 22-page printable planner built for Edwards County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.