When to Plant Vinca (Annual) in Coryell 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.
Coryell County, Texas is in USDA Zone 8b. The average last spring frost is March 16 and the first fall frost is November 15, giving you a growing season of approximately 244 days.
At an elevation of 3,488 feet, Coryell County receives approximately 65 inches of rainfall annually with predominantly clay soil. Summer highs average 91°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.
Coryell County Soil Profile
Soil Type
Clay
Soil pH
7-8.3
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 2.3" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Apr | 4.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 9.1" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 9" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.2" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 7.1" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Coryell County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Vinca (Annual) Planting Timeline — Coryell County, TX
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 5 | Jan 5 – Jan 19 |
| Transplant Outdoors | March 2 | Mar 2 – Mar 16 |
| Bloom | May 11 | May 11 – Oct 12 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors |
| April | — |
| 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
244 days in Coryell County
Growing Tips for Coryell 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 Coryell County, TX?
Coryell County is in Zone 8b with an average last frost of March 16. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Coryell County, TX?
Coryell County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 16 and first fall frost is November 15.
Your Coryell County Garden Planner — Free
A 22-page printable planner built for Coryell 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.