How to Grow Vinca (Madagascar Periwinkle): Planting, Spacing, Care & Bloom
Quick answer
Start indoors 10 to 8 weeks before outdoor planting after frost (UMN/ISU 10; Purdue HO-14 8). Transplant at last frost when soil is warm — Clemson above about 60°F. NC State Low poison severity — vinca alkaloids. Not the same as ground-cover periwinkle (Vinca minor/major).
Vinca at a glance
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated
Safety: NC State poison severity Low for Catharanthus roseus. “Consuming large quantities of the plant can lead to vomiting, diarrhea, low blood pressure, hallucinations, depression, tremors, seizures, coma, death.” Toxic principle: vinca alkaloids. Poison parts include flowers, fruits, leaves, roots, seeds, and stems. Problem for cats, dogs, and horses. Not medical advice. (NC State Catharanthus roseus)
Annual vinca / Madagascar periwinkle (Catharanthus roseus). Not ground-cover periwinkle (Vinca minor / V. major).
Sourced from university extension guides. For dates where you live, use the ZIP planting planner.
Planting timing
UMN: “Vinca seeds can be started indoors about 10 weeks prior to the anticipated outdoor planting date.” (UMN vinca) Iowa State germination table: Vinca (Catharanthus roseus) 10 weeks sowing to planting. (ISU germination table) Purdue HO-14 lists 8 weeks. Clemson: plant outside once the ground is warm, usually in May when soil temperatures are above 60°F — too early invites fungus or root rot. (Clemson HGIC 1158) Planner: Start indoors last frost −10 to −8; Transplant last frost 0 with warm soil (≥60°F).
Depth and spacing
Clemson: about 1–2 feet high and as wide. NC: height 6–18 in; width 8–12 in; space <12 inches. Lightly cover seed (UMN).
Sun, soil and water
Full sun (to part shade — NC); well-drained; heat/drought tolerant (Clemson/NC). Drainage is critical for root-rot prevention (Clemson).
Care
Modern hybrids generally need no deadheading (NC/Clemson). Self-sows sometimes (Clemson).
Bloom
May/June through frost (Clemson/NC); blooms in heat (NC).
Pests and diseases
Clemson: root/stem rots and foliar diebacks — good drainage; do not plant into cold/wet soil. Cultural drainage first for Phytophthora risk.
Related: ZIP planner · organic pest control
Frequently asked questions
When do I plant annual vinca?
Start 10 to 8 weeks before last frost; transplant at last frost when soil is warm (≥60°F Clemson).
Same as periwinkle ground cover?
No — bedding vinca is Catharanthus roseus; ground cover is Vinca minor/major.
Is it poisonous?
NC State Low severity — vinca alkaloids if large amounts are eaten.
Sources
- NC State Extension: NC State Catharanthus roseus
- University of Minnesota Extension: Vinca
- Iowa State University Extension: ISU germination table
- Clemson Cooperative Extension: Clemson HGIC 1158