Blog

When to plant Vinca (Annual) in Mobile County County,

Mobile County County sits in cold Zone 9a. Plant Vinca (Annual) February 10–February 24 for the single annual harvest; the November 24 first frost closes the window.

When to Plant Vinca (Annual) in Mobile County, AL

Mobile County, Alabama Zone 9a June

Your June gardening checklist

A quick June briefing for Mobile County, Alabama gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 3
Avg. first frost November 24
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Start harvesting vinca (annual)

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

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

Instant PDF download. No spam, unsubscribe any time.

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.

Mobile County, Alabama is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 24, giving you a growing season of approximately 266 days.

At an elevation of 101 feet, Mobile County receives approximately 48.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°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.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Mobile County, AL (Zone 9a) Long season
266 days
Last Spring Frost March 3
266 growing days
First Fall Frost November 24

Mobile County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.1

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Dec 11 Transplant: Jan 29 🌸 Bloom: Apr 9 – Oct 8
Recommended (50%) ✓ Fits season (35 days to spare)
Start indoors: Dec 23 Transplant: Feb 10 🌸 Bloom: Apr 21 – Oct 20
Safe Start (90%) ✓ Fits season (35 days to spare)
Start indoors: Jan 9 Transplant: Feb 27 🌸 Bloom: May 8 – Nov 6

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 Mobile County

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

Soil pH

Your soil pH (4.8–6.1) is more acidic than Vinca (Annual) prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Vinca (Annual) prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

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 266-day season

Sow every 8 weeks. Last sowing by Aug 26 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/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 3.7" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 2.2" 4.9" 0" ✅ Rainfall sufficient
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4" 0" ✅ Rainfall sufficient
Jul 2.2" 5.5" 0" ✅ Rainfall sufficient
Aug 2.2" 4.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.2" 4.3" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Mobile 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 ~1,820 GDD — county provides 6,051 GDD Excellent fit

Vinca (Annual) Planting Timeline — Mobile County, AL

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors December 23 Dec 23 – Jan 6
Transplant Outdoors February 10 Feb 10 – Feb 24
Bloom April 21 Apr 21 – Oct 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
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: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

266 days in Mobile County

Growing Tips for Vinca (Annual) in Mobile County

Direct sow Vinca (Annual) outdoors after March 03 in Mobile County when soil has warmed and frost danger has passed.

Sandy soil in Mobile 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 97°F in Mobile 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 Mobile County, AL?

Mobile County is in Zone 9a with an average last frost of March 3. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mobile County, AL?

Mobile County, Alabama is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 24.

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

In Mobile County County, , plant Vinca (Annual) after the last frost (around March 3) and before the first frost (around November 24). Best results when soil holds above 50°F.

What growing zone is Mobile County County, for Vinca (Annual)?

Mobile County County sits in USDA Zone 9a. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.

Can Vinca (Annual) grow in Mobile County County's climate?

Yes — Vinca (Annual) grows well in Mobile County County's temperate climate. Mobile County County averages a 266-day frost-free season, with last frost around March 3 and first frost around November 24.

🌱

Your Mobile County Garden Planner — Free

A 22-page printable planner built for Mobile 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Mobile County, AL. 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.