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

Plant Vinca (Annual) in Washington County County, between February 12 and February 26 — the only viable window. Zone 9a's short season (260 frost-free days) rules out a fall crop.

When to Plant Vinca (Annual) in Washington County, FL

Washington County, Florida Zone 9a June

Washington County, Florida gardeners: here's your June plan

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

Avg. last frost March 5
Avg. first frost November 20
Soil temp (4") 83°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Pick vinca (annual)

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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  • 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.

Washington County, Florida is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 20, giving you a growing season of approximately 260 days.

At an elevation of 196 feet, Washington County receives approximately 50.6 inches of rainfall annually with predominantly sand 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. 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
Washington County, FL (Zone 9a) Long season
260 days
Last Spring Frost March 5
260 growing days
First Fall Frost November 20
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Washington County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.9

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Dec 15 Transplant: Feb 2 🌸 Bloom: Apr 13 – Oct 12
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Dec 25 Transplant: Feb 12 🌸 Bloom: Apr 23 – Oct 22
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Jan 16 Transplant: Mar 6 🌸 Bloom: May 15 – Nov 13

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 Washington County

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

Soil pH

Your soil pH (4.8–5.9) is more acidic than Vinca (Annual) prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Vinca (Annual).

Organic Matter

Organic matter is low (1.7%). 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 260-day season

Sow every 8 weeks. Last sowing by Aug 22 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 2" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 2.2" 2.5" 0" ✅ Rainfall sufficient
Apr 2.2" 2.2" 0" ✅ Rainfall sufficient
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 6.8" 0" ✅ Rainfall sufficient
Jul 2.2" 8.5" 0" ✅ Rainfall sufficient
Aug 2.2" 6.5" 0" ✅ Rainfall sufficient
Sep 2.2" 7.3" 0" ✅ Rainfall sufficient
Oct 2.2" 4" 0" ✅ Rainfall sufficient
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington 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 5,915 GDD Excellent fit

Vinca (Annual) Planting Timeline — Washington County, FL

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors December 25 Dec 25 – Jan 8
Transplant Outdoors February 12 Feb 12 – Feb 26
Bloom April 23 Apr 23 – Oct 22

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
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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

260 days in Washington County

Growing Tips for Vinca (Annual) in Washington County

Direct sow Vinca (Annual) outdoors after March 05 in Washington County when soil has warmed and frost danger has passed.

Sandy soil in Washington 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 Washington 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 Washington County, FL?

Washington County is in Zone 9a with an average last frost of March 5. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, FL?

Washington County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 20.

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

In Washington County County, , plant Vinca (Annual) after the last frost (around March 5) and before the first frost (around November 20). Best results when soil holds above 50°F.

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

Washington 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 Washington County County's climate?

Yes — Vinca (Annual) grows well in Washington County County's temperate climate. Washington County County averages a 260-day frost-free season, with last frost around March 5 and first frost around November 20.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington 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 Washington County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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