Euphorbia triangularis is a succulent, deciduous, spiny tree, usually with a single trunk and several branches clustered in whorls and can be 3, 4 or 5 angled. Leaves are 'tongue-like' and very small. Paired 1/2" spines project laterally and up, and are very sharp and thin,
The river euphorbia has yellowish green to yellow cyathia in midwinter. The fruit is globose and three-lobed, clustered as reddish beads along the stem top ridges
It is an easy species to grow that is suited for any well drained soil in full sun. But young plant are happy growing indoors, where they can easily reach the ceiling.
Give the plant an airy growing medium which mainly consists of non organic material such us clay, pumice, lava grit, and only a little peat or leaf-mould.
Water regularly during the active growing season. No water should ever be allowed to stand around the roots. Keep almost completely dry in winter. If plant becomes very red, this is a sign that the roots have not developed properly. It can tolerate moderate shade, and a plant that has been growing in shade should be slowly hardened off before placing it in full sun as the plant will be severely scorched if moved too suddenly from shade into sun. .
It makes an excellent and impenetrable barrier. It is a moderately fast grower, and will quickly become large landscape masterpieces in just 3-5 years.
The plant is poisonous and skin contact with the sap can cause blistering.