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

Morton County's short 180-day growing season means one Vinca (Annual) planting between April 27 and May 11. No fall crop in Zone 6b.

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

Morton County, Kansas Zone 6b July

Top priorities for Morton County, Kansas gardeners in July

Your garden in Morton County, Kansas is working on a schedule, even when you're not. Here's where you should be this July.

Avg. last frost April 20
Avg. first frost October 17
Soil temp (4") 82°F
Watering High
Pest pressure High
Daylight 14.3 hrs
  1. Collect vinca (annual) at their peak

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

August prep starts now
  • 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.

Morton County, Kansas is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 1,054 feet, Morton County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Vinca (Annual) during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Morton County, KS (Zone 6b) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Morton County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.4

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Feb 3 Transplant: Apr 21 🌸 Bloom: Jun 30 – Oct 13
Recommended (50%) ✗ May not fit
Start indoors: Feb 9 Transplant: Apr 27 🌸 Bloom: Jul 6 – Oct 19
Safe Start (90%) ✓ Fits season (2 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 Morton County

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

Soil pH

Your soil pH (6.7–7.4) 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 Morton County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.5%). 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 180-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 1.8" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 2.5" 0" ✅ Rainfall sufficient
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.4" 0" ✅ Rainfall sufficient
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 1.5" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Morton 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 ~1,460 GDD — county provides 3,285 GDD Excellent fit

Vinca (Annual) Planting Timeline — Morton County, KS

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors April 27 Apr 27 – May 11
Bloom July 6 Jul 6 – Oct 19

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

180 days in Morton County

Growing Tips for Vinca (Annual) in Morton County

Direct sow Vinca (Annual) outdoors after April 20 in Morton County when soil has warmed and frost danger has passed.

Morton County receives only 24" of rain annually. Vinca (Annual) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Morton County, KS?

Morton County is in Zone 6b with an average last frost of April 20. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Morton County, KS?

Morton County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 17.

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

In Morton County, KS, plant Vinca (Annual) after the last frost (around April 20) and before the first frost (around October 17). Best results when soil holds above 50°F.

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

Morton 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 Morton County's climate?

Yes — Vinca (Annual) grows well in Morton County's temperate climate. Morton County averages a 180-day frost-free season, with last frost around April 20 and first frost around October 17.

🌱

Your Morton County Garden Planner — Free

A 22-page printable planner built for Morton 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 Morton County, KS. Local conditions may vary. Last updated: July 2026.

Sources & credits

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