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

Montgomery County, Texas Zone 9a June

Top priorities for Montgomery County, Texas gardeners in June

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

Avg. last frost February 18
Avg. first frost December 1
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Collect vinca (annual) at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to July
  • 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.

Montgomery County, Texas is in USDA Zone 9a. The average last spring frost is February 18 and the first fall frost is December 1, giving you a growing season of approximately 286 days.

At an elevation of 180 feet, Montgomery County receives approximately 62.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°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.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Montgomery County, TX (Zone 9a) Year-round
286 days
Last Spring Frost February 18
286 growing days
First Fall Frost December 1

Montgomery County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Dec 2 Transplant: Jan 20 🌸 Bloom: Mar 31 – Sep 29
Recommended (50%) ✓ Fits season (55 days to spare)
Start indoors: Dec 10 Transplant: Jan 28 🌸 Bloom: Apr 8 – Oct 7
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: Dec 29 Transplant: Feb 16 🌸 Bloom: Apr 27 – Oct 26

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 Montgomery County

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Montgomery County warms quickly in spring but drains fast. Vinca (Annual) will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.8%). Add 2-3 inches of compost before planting 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 286-day season

Sow every 8 weeks. Last sowing by Sep 02 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 1.6" 0" ❄️ Dormant
Feb 2.2" 2.1" 0.1" 💧 Light watering
Mar 2.2" 4.5" 0" ✅ Rainfall sufficient
Apr 2.2" 6.5" 0" ✅ Rainfall sufficient
May 2.2" 8.2" 0" ✅ Rainfall sufficient
Jun 2.2" 11" 0" ✅ Rainfall sufficient
Jul 2.2" 8" 0" ✅ Rainfall sufficient
Aug 2.2" 7.1" 0" ✅ Rainfall sufficient
Sep 2.2" 5.3" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 2.2" 1.6" 0.6" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Montgomery 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 ~1,760 GDD — county provides 6,314 GDD Excellent fit

Vinca (Annual) Planting Timeline — Montgomery County, TX

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors December 10 Dec 10 – Dec 24
Transplant Outdoors January 28 Jan 28 – Feb 11
Bloom April 8 Apr 8 – Oct 7

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

Month-by-Month Timeline

MonthActivities
January Transplant Outdoors
February Transplant Outdoors
March
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

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

286 days in Montgomery County

Growing Tips for Vinca (Annual) in Montgomery County

Direct sow Vinca (Annual) outdoors after February 18 in Montgomery County when soil has warmed and frost danger has passed.

Sandy soil in Montgomery County dries quickly — mulch Vinca (Annual) with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in Montgomery County, provide afternoon shade for Vinca (Annual) and water deeply in the morning.

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 Montgomery County, TX?

Montgomery County is in Zone 9a with an average last frost of February 18. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montgomery County, TX?

Montgomery County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 18 and first fall frost is December 1.

🌱

Your Montgomery County Garden Planner — Free

A 22-page printable planner built for Montgomery County (Zone 9a). 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 Montgomery County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

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