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When to plant Vinca (Annual) in Pawnee County, KS

In Pawnee County, Vinca (Annual) is a spring-only crop. Plant April 25–May 9 once soil hits 50°F.

When to Plant Vinca (Annual) in Pawnee County, KS

Pawnee County, Kansas Zone 6b June

Your June game plan for Pawnee County, Kansas

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

Avg. last frost April 18
Avg. first frost October 16
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Time to start vinca (annual) inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

A few tasks this June that'll pay off in 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.

Pawnee County, Kansas is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 16, giving you a growing season of approximately 181 days.

At an elevation of 621 feet, Pawnee County receives approximately 34.4 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Vinca (Annual) during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Pawnee County, KS (Zone 6b) Moderate season
181 days
Last Spring Frost April 18
181 growing days
First Fall Frost October 16

Pawnee County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 3 Transplant: Apr 21 🌸 Bloom: Jun 30 – Oct 13
Recommended (50%) ✗ May not fit
Start indoors: Feb 7 Transplant: Apr 25 🌸 Bloom: Jul 4 – Oct 17
Safe Start (90%) ✓ Fits season (3 days to spare)
Start indoors: Feb 22 Transplant: May 10 🌸 Bloom: Jul 19 – Nov 1

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 Pawnee County

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

Soil pH

Your soil pH (6.8–7.7) 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 Pawnee County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). 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)

2
successive plantings in your 181-day season

Sow every 8 weeks. Last sowing by Jul 18 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
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 5.2" 0" ✅ Rainfall sufficient
Jun 2.2" 6.2" 0" ✅ Rainfall sufficient
Jul 2.2" 3.8" 0" ✅ Rainfall sufficient
Aug 2.2" 3.7" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Pawnee 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 ~1,340 GDD — county provides 3,031 GDD Excellent fit

Vinca (Annual) Planting Timeline — Pawnee County, KS

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors April 25 Apr 25 – May 9
Bloom July 4 Jul 4 – Oct 17

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors
May Transplant Outdoors
June
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 6b

📆 Growing Season

181 days in Pawnee County

Growing Tips for Vinca (Annual) in Pawnee County

Direct sow Vinca (Annual) outdoors after April 18 in Pawnee 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 Pawnee County, KS?

Pawnee County is in Zone 6b with an average last frost of April 18. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pawnee County, KS?

Pawnee County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 16.

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

In Pawnee County, KS, plant Vinca (Annual) after the last frost (around April 18) and before the first frost (around October 16). Best results when soil holds above 50°F.

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

Pawnee County sits in USDA Zone 6b. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.

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

Yes — Vinca (Annual) grows well in Pawnee County's temperate climate. Pawnee County averages a 181-day frost-free season, with last frost around April 18 and first frost around October 16.

🌱

Your Pawnee County Garden Planner — Free

A 22-page printable planner built for Pawnee County (Zone 6b). 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 Pawnee County, KS. 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.