Euphorbia Trigona, or the African Milk Tree as it's commonly known, is a highly architectural and curious houseplant. Easy to look after, pest resistant and a fast grower means it makes the perfect specimen that adds interest to a sunny spot.
Like many in the Euphorbia genus, it's a mix between a cactus and a succulent plant but has traits familiar with both.
The "Trigona" name comes from the plant's stems which have three distinct sides creating a Triangular effect (if it has four sides, you may have a Euphorbia Acrurensis instead). As each side reaches the edge, it rounds out slightly to create a ridge. Along the ridge, two thorns will form every cm or so and in between those, a leaf will normally grow.
The leaves have a teardrop shape and tend to be present for only short periods, a growing season or two. If you provide poor care, then the leaves will be the first to drop off.
Even if you end up with a leafless stem, it's still a striking and handsome houseplant.
Like the majority of Euphorbia plants, they really don't like being touched or played with. The thorns will deter most people and pets, but if this isn't enough, it will ooze a latex sap that's both unpleasant to taste and also highly irritating to eyes and mucous membranes like those found in the mouth .
If you can live with those negatives, it's an adaptable houseplant that only has basic and simple to follow care needs. In return it will grow pretty fast and provide all-year interest.
These are succulents and not true cacti, so intense pounding sun isn't something your plant wants or will enjoy. Coming from Central Africa, they're well adapted and expecting to deal with heat and some sun though, so they do need either bright light all day or some sunlight for an hour or two.
You can also put them outside during Summer providing the location you pick for it gets at least some partial shade.
You should not suddenly move your plant into intense sunlight if it's been in a darker spot for a while, or you'll risk scorching. Get them acclimatised for a week or so by moving them into the sun for an hour or so a day then back into shade again, gradually increasing the time in the sun.
They absolutely do not do well in lower light settings. This plant needs good light levels and if you can't give this, a grow light will be required.
If the light being received is too low, you'll have little to no new growth. New leaves will only grow on one side of the plant and stems may also bend towards light sources rather than straight upwards.
Even plants grown in good light levels might have some of these issues if the light is only coming from one direction. If this happens, rotate the planter 1/4 turn every week or two for more consistent growth.
They can be easily overwatered, so if there is any doubt whether your plant needs a top-up or not, wait a few more days to be safe.