When to plant Vinca (Annual) in McCone County, MT
McCone County's 131-day season only supports one Vinca (Annual) planting per year. Sow between May 28 and June 11 for the best chance at full maturity before September 22.
When to Plant Vinca (Annual) in McCone County, MT
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.
McCone County, Montana is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 22, giving you a growing season of approximately 131 days.
At an elevation of 5,568 feet, McCone County receives approximately 22 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Vinca (Annual) to ensure they mature before fall.
McCone County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.2
Drainage
Well Drained
Monthly Watering Guide for Vinca (Annual)
Vinca (Annual) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Vinca (Annual) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Jun | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Jul | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Aug | 4.3" | 2.3" | 2" | 💧 Light watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in McCone County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Vinca (Annual) Planting Timeline — McCone County, MT
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 26 | Feb 26 – Mar 12 |
| Transplant Outdoors | May 28 | May 28 – Jun 11 |
| Bloom | August 6 | Aug 6 – Oct 8 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
131 days in McCone County
Growing Tips for McCone County
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 McCone County, MT?
McCone County is in Zone 4a with an average last frost of May 14. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is McCone County, MT?
McCone County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 22.
When should I plant Vinca (Annual) in McCone County, MT?
In McCone County, MT, plant Vinca (Annual) after the last frost (around May 14) and before the first frost (around September 22). Best results when soil holds above 50°F.
What growing zone is McCone County, MT for Vinca (Annual)?
McCone County sits in USDA Zone 4a. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.
Can Vinca (Annual) grow in McCone County's climate?
Yes — Vinca (Annual) grows well in McCone County's temperate climate. McCone County averages a 131-day frost-free season, with last frost around May 14 and first frost around September 22.
Your McCone County Garden Planner — Free
A 22-page printable planner built for McCone County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.