When to Plant Vinca (Annual) in Webb 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.
Webb County, Texas is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 9, giving you a growing season of approximately 303 days.
At an elevation of 3,543 feet, Webb County receives approximately 50.9 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Vinca (Annual) may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.
Webb County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.7
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Mar | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Apr | 4.3" | 5" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.3" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Nov | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Dec | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Webb County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Vinca (Annual) Planting Timeline — Webb County, TX
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 1 | Dec 1 – Dec 15 |
| Transplant Outdoors | January 12 | Jan 12 – Jan 26 |
| Bloom | March 23 | Mar 23 – Oct 5 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors |
| February | — |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | Start Indoors |
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 9b
📆 Growing Season
303 days in Webb County
Growing Tips for Webb 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 Webb County, TX?
Webb County is in Zone 9b with an average last frost of February 9. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Webb County, TX?
Webb County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 9.
Your Webb County Garden Planner — Free
A 22-page printable planner built for Webb County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.