I purchased some annual vinca (Catharanthus roseus), also known as Madagascar periwinkle, part way through the season last year to rejuvenate some tired planters. These are amazing annuals for hot, dry conditions. They bloomed not stop, even better than verbena. And, lucky for me, they are deer and rabbit resistant.

Varieties and Sources

I’m not sure why, but annual vinca seeds are hard to find. I was not able to find any from my normal Canadian seed suppliers.

Swallowtail Seeds

• Mediterranean Burgundy Halo Vinca
• Tattoo Blueberry Vinca

Seed Starting Guide

Our last frost date is around May 13 according to the almanac however it’s rare for us not to have a cold snap before the May 24 weekend. Based on research, this is my sowing and planting plan for 2026:

Start Date

• March 10–15 (10–11 weeks before May 24)
• Germination temp: 24-27°C (warmer than other seeds)
• Days to germination: 10-21 days

Sowing Method

• Sow in cell packs or germination trays (I’m going to use germination trays)
• Cover lightly and keep tray covered until sprouting
• Needs darkness to germinate – cover with newspaper, keep out of direct sun
• Consider starting these on the floor (as it’s heated and I can put them under the tables for darkness)

Growing On

• Pot up once true leaves appear
• Temp: 20-24°C
• Light: 14–16 hours (needs strong light)
• Do NOT overwater as they are prone to rot
• Fertilize when 3 to 4 weeks old.

Planting Out

• Frost tender
• Dislikes cold soil
• Plant after May 24 (early June best) when nights above 12°C