African Milk Tree
Euphorbia trigona
A tall ridged column of a plant, easy enough to keep — but the milky sap stings, so it is handled in gloves.
- Type
- Houseplant · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Sunlight
- Part shade
- Feeding
- All-purpose balanced
- Frost tolerant
- No
- Mar–Dec Spring Growth
- Jan–Mar Spring Growth
- Plant spacing
- 15.7 in
- In-row spacing
- 15.7 in
- Between rows
- 19.7 in
- Square-foot density
- Not suited to SFG
- Root system
- Shallow, wide and fine
- Working depth
- 4–12 in
- Can reach
- 18 in down where the soil allows
- Spread
- 24 in–3.5 ft across, about 1.5–2.5× the width of the plant
- Shallowest pot
- 6 in of soil
Roots run out flat and near the surface to catch light rain before it drains past, and they rot in ground that stays wet. Width of pot and sharpness of drainage matter to it; depth of pot hardly does.
The habit is African Milk Tree’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Mealybugs Mealybugs tucked into the ridges and crevices of the stems
- Root & crown rot Root rot from watering too often
- Leggy seedlings Weak, stretched growth when the light is too poor
- Leaves dropped after a cold spell or a cold draft
- Milky sap that irritates skin and eyes — wear gloves for any cutting
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Green lacewing Chrysoperla carneaHunts Mealybugs
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Hoverfly SyrphidaeHunts Mealybugs
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Mealybugs
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
Houseplants, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com