Pencil cactus care guide
Euphorbia tirucalli
Also known as: Milk bush, Sticks on Fire
Pets and children
Considered toxic
The white latex from a broken stem is strongly irritating: it burns skin, can badly hurt the eyes, and inflames the mouth or causes vomiting if eaten; keep it well out of reach, rinse sap off with running water, and consult a veterinarian or doctor if swallowed.
How often to water Pencil cactus
- Spring–Summer (Mar–Sep)
- Every 7 days
- A summer grower: as a guide, water well two or three days after the topsoil dries, in the morning or evening in midsummer.
- Autumn (Oct–Nov)
- Every 10 days
- As it cools, water less often, about a week after the soil dries.
- Winter (Dec–Feb)
- Every month
- Resting indoors, moisten lightly about once a month on a warm day, or every two to three weeks in a heated room, as a guide.
Light and placement for Pencil cactus
A sunny, airy spot as a guide: it thrives in direct sun outdoors from spring to fall, and indoors it wants the brightest window, since low light makes the stems thin, droopy and pale.
Overwintering Pencil cactus
Overwintering guide: 5°C (41°F) or above
Tender: keep it above about 5°C, moving it to a bright window before nights dip below 10°C and watering little; dropping some fine stem tips in winter is generally normal.
Fertilizing and repotting Pencil cactus
Fertilizer
Feed lightly: diluted liquid fertilizer about once a month from May to September, none in fall and winter, as too much makes lanky stems.
When to repot
Spring–Summer (Mar–Sep)
Common problems with Pencil cactus
- Watered at summer rates in winter, the roots rot and the stems blacken.
- In a dark room the stems thin, droop and gradually die back.
- Sap gets on skin or in the eyes during pruning and causes a rash.
Tips for growing Pencil cactus
- Prune with gloves and eye protection, and rinse the cut sap away with water.
- For cuttings, let the cut dry a few days, then set it in dry mix and wait for roots.
- Brown, soft stem bases are the sign of overwatering.
These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.
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