Overwintering guide
How to overwinter euphorbia mammillaris
Winter watering
Cut watering right back — euphorbia mammillaris uses far less while growth slows, and cold, wet compost is the usual cause of winter root rot. Stop feeding until spring.
The mistake that kills euphorbia mammillaris in winter
Watering on the same schedule as summer. In winter that keeps the roots sodden while the plant is barely drinking, and euphorbia mammillaris rots from the base.
More euphorbia mammillaris care
Overwintering euphorbia mammillaris — FAQ
Does euphorbia mammillaris need to come indoors for winter?
Euphorbia mammillaris is hardy to roughly USDA zone 10 — winter lows around -1°C. That means it will not survive frost and needs to come inside. Euphorbia mammillaris is frost-tender, so overwintering means bringing it inside and letting it rest rather than pushing it to grow. Move it indoors well before the first frost, give it the brightest spot you have (light levels indoors drop sharply in winter), and keep it away from both cold window glass and hot radiators — the swing between the two does more damage than the cold itself.
When should I move euphorbia mammillaris for winter?
Bring indoors when nights start dropping below about 10°C, ahead of the first frost.
How often should I water euphorbia mammillaris in winter?
Cut watering right back — euphorbia mammillaris uses far less while growth slows, and cold, wet compost is the usual cause of winter root rot. Stop feeding until spring.
What kills euphorbia mammillaris over winter?
Watering on the same schedule as summer. In winter that keeps the roots sodden while the plant is barely drinking, and euphorbia mammillaris rots from the base.