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When to Plant Vinca (Annual) in Dixon County, NE

Dixon County, Nebraska Zone 5a June

Your June game plan for Dixon County, Nebraska

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
A few tasks this June that'll pay off in July
  • Starting indoors: vinca (annual)
  • 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.

Dixon County, Nebraska is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 654 feet, Dixon County receives approximately 26.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Vinca (Annual) to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Dixon County, NE (Zone 5a) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7
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Dixon County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.4

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Feb 4 Transplant: May 6 🌸 Bloom: Jul 15 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Feb 12 Transplant: May 14 🌸 Bloom: Jul 23 – Oct 8
Safe Start (90%) ✗ May not fit
Start indoors: Feb 26 Transplant: May 28 🌸 Bloom: Aug 6 – Oct 22

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 Dixon County

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

Soil pH

Your soil pH (6.2–7.4) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Dixon 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 160-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.6" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.2" 2.7" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 3.8" 0" ✅ Rainfall sufficient
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 2.5" 0" ✅ Rainfall sufficient
Oct 2.2" 1.6" 0.6" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Dixon 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 ~1,040 GDD — county provides 2,080 GDD Excellent fit

Vinca (Annual) Planting Timeline — Dixon County, NE

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors May 14 May 14 – May 28
Bloom July 23 Jul 23 – Oct 8

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April
May Transplant Outdoors
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December
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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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

160 days in Dixon County

Growing Tips for Vinca (Annual) in Dixon County

Direct sow Vinca (Annual) outdoors after April 30 in Dixon 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 Dixon County, NE?

Dixon County is in Zone 5a with an average last frost of April 30. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dixon County, NE?

Dixon County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.

🌱

Your Dixon County Garden Planner — Free

A 22-page printable planner built for Dixon County (Zone 5a). 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 Dixon County, NE. 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.