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When to Plant Vinca (Annual) in Fannin County, TX

Fannin County, Texas Zone 8a August

Your August gardening checklist

Each item below is timed to Fannin County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 16
Avg. first frost November 15
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.2 hrs
  1. Start harvesting vinca (annual)

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong September, finish these tasks
  • First harvests: vinca (annual)

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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.

Fannin County, Texas is in USDA Zone 8a. 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 282 feet, Fannin County receives approximately 63.8 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Vinca (Annual) during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Fannin County, TX (Zone 8a) Long season
244 days
Last Spring Frost March 16
244 growing days
First Fall Frost November 15

Fannin County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Dec 27 Transplant: Feb 28 🌸 Bloom: May 9 – Sep 26
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Jan 5 Transplant: Mar 9 🌸 Bloom: May 18 – Oct 5
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🌸 Bloom: Jun 11 – Oct 29

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 Fannin County

How your county's soil matches Vinca (Annual)'s growing requirements.

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Vinca (Annual) prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Fannin County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Vinca (Annual).

How to Plant Vinca (Annual)

0.1"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Vinca (Annual)

4
successive plantings in your 244-day season

Sow every 8 weeks. Last sowing by Aug 17 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.2" 4.3" 0" ✅ Rainfall sufficient
Apr 2.2" 6.3" 0" ✅ Rainfall sufficient
May 2.2" 8.7" 0" ✅ Rainfall sufficient
Jun 2.2" 11.1" 0" ✅ Rainfall sufficient
Jul 2.2" 7.7" 0" ✅ Rainfall sufficient
Aug 2.2" 7.9" 0" ✅ Rainfall sufficient
Sep 2.2" 6.2" 0" ✅ Rainfall sufficient
Oct 2.2" 4.3" 0" ✅ Rainfall sufficient
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Fannin 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) needs ~1,280 GDD — county provides 3,904 GDD Excellent fit

Vinca (Annual) Planting Timeline — Fannin County, TX

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors January 5 Jan 5 – Jan 19
Transplant Outdoors March 9 Mar 9 – Mar 23
Bloom May 18 May 18 – Oct 5

Plant 0.1" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
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

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

244 days in Fannin County

Growing Tips for Vinca (Annual) in Fannin County

Direct sow Vinca (Annual) outdoors after March 16 in Fannin 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 →

Frequently Asked Questions

When should I plant Vinca (Annual) in Fannin County, TX?

Fannin County is in Zone 8a 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 Fannin County, TX?

Fannin County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 16 and first fall frost is November 15.

🌱

Your Fannin County Garden Planner — Free

A 22-page printable planner built for Fannin County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Fannin County, TX. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.