Periwinkle
Catharanthus roseus · also called Sadabahar, Madagascar periwinkle
Flowering
- Light
- Sunny, Part sun
- Pot size
- Small pot (up to about 5 litres)
- Care level
- Easy
- Year round or seasonal
- Kept year to year; in a pot, keep it above about 12.8 °C (55 °F)
- Pets
- ASPCA: toxic to pets
Light and position
Full sun to part shade.
Size and pot
NC State lists 6 to 18 inches. Our pot band: small pot (up to about 5 litres).
Watering
NC State rates its drought tolerance moderate to high and notes it keeps flowering through heat.
Potting mix and feeding
Moist but well-drained soil; it is prone to Phytophthora root and stem rot where soil stays wet.
Growing through the year
Grown from seed; it suits containers and hanging baskets.
Winter outdoors
Cold limit in a pot: about 12.8 °C (55 °F). NC State calls it a tender perennial: perennial in zone 10 and higher, treated as an annual in colder regions, and flowering until frost. For tender plants we follow NC State’s container chapter: bring them inside once nights drop to 55 °F.
| Your coldest winter nights | What to do |
|---|---|
| Coldest nights 15 °C or warmer | Can stay out through this winter |
| Coldest nights 10 to 15 °C | Move it to shelter before nights fall to 12.8 °C |
| Coldest nights 5 to 10 °C | Move it to shelter before nights fall to 12.8 °C |
| Coldest nights 0 to 5 °C | Move it to shelter before nights fall to 12.8 °C |
| Light frost: nights down to about −5 °C | Move it to shelter before nights fall to 12.8 °C |
| Hard frost: nights below −5 °C | Move it to shelter before nights fall to 12.8 °C |
A plant can stay out only when its limit is below the coldest night in your band; a limit equal to that night counts as needing shelter. A rare cold snap, wind or a wet pot can still damage plants. We convert °F to °C with NIST’s formula.
Watch for
Root rots and leaf spot; NC State lists no common insect pests.
Pets and people
ASPCA lists periwinkle as toxic to dogs, cats and horses (vinca alkaloids). Signs range from vomiting and diarrhoea to tremors, seizures and, in serious cases, death.
General gardening information, not professional advice. Plant toxicity details are a starting point, not veterinary or medical advice: if a pet or child may have eaten a plant, contact a veterinarian or doctor promptly.
Care level: NC State’s maintenance rating (Low). Pot band and summary wording are ours, based on the sources below.