When to Plant Vinca (Annual) in Colfax County, NE
Your June planting checklist for Colfax County, Nebraska
Your Colfax County, Nebraska garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
Looking ahead to July
- Starting indoors: vinca (annual)
- First harvests: vinca (annual)
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.
Colfax County, Nebraska is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.
At an elevation of 525 feet, Colfax County receives approximately 25 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.
Colfax County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.7
Drainage
Well Drained
Vinca (Annual) Planting Risk Windows
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 Colfax County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (6.4–7.7) 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 Colfax County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Vinca (Annual).
Organic Matter
Organic matter is excellent (4.0%) — Vinca (Annual) will thrive.
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.
Vinca (Annual) Water Budget
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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Colfax 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) Planting Timeline — Colfax County, NE
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 4 | Feb 4 – Feb 18 |
| Transplant Outdoors | April 29 | Apr 29 – May 13 |
| Bloom | July 8 | Jul 8 – Sep 30 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Only during dry spells
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5b
📆 Growing Season
172 days in Colfax County
Growing Tips for Vinca (Annual) in Colfax County
Direct sow Vinca (Annual) outdoors after April 22 in Colfax 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 →
Vinca (Annual) in Other Locations
Frequently Asked Questions
When should I plant Vinca (Annual) in Colfax County, NE?
Colfax County is in Zone 5b with an average last frost of April 22. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Colfax County, NE?
Colfax County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 11.
Your Colfax County Garden Planner — Free
A 22-page printable planner built for Colfax County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.