Euphorbiaceae, A Family of Great Variety
By Marie Harrison (can2grow) September 18, 2012
When we think of Euphorbia, we often think of thorny plants such as crown of thorns or those that ooze milky sap when cut or broken, such as the milk bush or pencil tree. Many other members of the Euphorbiaceae family exist that are not easily identified by these highly observable characteristics. Many favorite landscape plants belong to this family, as well as some exotic invasive plants that are best avoided.
One genus is popular because of its showy pendulous crimson tassels. Acalypha hispida (chenille plant, foxtail, red-hot cat’s tail) can grow as a sparsely branched shrub reaching 6 to 12 feet tall in tropical areas (USDA Zones 10b-12). The very similar but smaller Acalypha pendula (dwarf chenille plant) is popular in hanging baskets where its tassels cascade over the sides.
You would never guess just by looking at the foliage that Acalypha wilkesiana (copper leaf) is a member of the same genus as the two listed above. Growing as an evergreen shrub that can get up to 10 feet tall, it bears small, inconspicuous catkinlike racemes (flower clusters) that are mostly hidden in the foliage. Several different cultivars are available. ‘Marginata’ sports coppery green, pink margined leaves. ‘Macrophylla’ has larger leaves variegated with bronze, cream, yellow, and red. Foliage of ‘Godseffiana’ is narrow and drooping with cream colored margins, while ‘Musiaca’ leaves are mottled with orange and red.
Most Acalypha are hardy only in tropical areas. While the common copperleaf has established itself in Zone 9a in central Florida, most are hardy only in Zones 10 to 11. Further north, plants can be overwintered in brightly lit indoor places, or they can be grown as annuals.
Codiaeum (croton) is another popular Euphorbiaceae. This group of plants can easily become a collector’s favorite, for there are hundreds of cultivars. My personal collection consists of half a dozen or so different cultivars, each with vastly different appearances. I grow them in containers and move them inside during the winter, for they are tropical plants hardy in Zones 10 and 11. See my article about crotons on Dave’s Garden.
Another beautiful member of the clan is the castor plant (Ricinus communis). Herbaceous to semiwoody, this large shrub or small tree is fast growing and colony-forming. Very attractive, large (12 to 30 inches across) glossy purplish or reddish palmate leaves with 5 to 11 deeply incised lobes make it easy to understand why this plant is popular in many landscapes.
Sharon Brown, in her article, “Castor Oil, Anyone?” gives an excellent description of these plants. If you decide to grow them in your garden, be aware that they are highly toxic. They have escaped cultivation in areas where they are hardy (Zones 8-11) and have become weeds in some places.
Two Euphorbiaceae that are now weeds in parts of the world are Triadica sebifera syn. Sapium sebiferum (popcorn tree, Chinese tallow tree) and Vernicia fordii syn. Aleurites fordii (tung oil tree). My article, “An Environmentally Safe Wood Preservative,” offers a more detailed look at the tung oil tree. I could not find an article on Dave's Garden about the popcorn tree, so it offers an opportunity for greater detail in a future article.
Euphorbia umbellata ‘Ruby’ (African milk bush) is another Euphorbiaceae in my collection of plants. Grown from a cutting given to me by a friend, this plant grows in a container and is moved into the greenhouse during the winter. In the tropics it grows up to ten feet tall. Even in the container, I find that I must take new cuttings every year or so in order to keep it reasonably sized. Formerly, this plant was classified as Synadenium grantii, and I noticed in my research two other synonyms, Synadenium pseudograntii and Synadenium umbellatum that are sometimes used. Dave’s Garden has it named Euphorbia bicompacta var. rubra. This plant, too, prompts another article. It’s funny how one thing leads to another and we garden writers never quite run out of topics.
The Euphorbiaceae family, as anyone can see with minimal investigation, is exceedingly varied. Within it are houseplants for the collector, landscape plants, poisonous plants, and plants for almost every purpose under the sun. The more I learn about this amazing family of plants, the more spurred I am to further study. That’s the way we hortimaniacs are. We can never learn all we want to know about the amazing world of plants.
Thanks to these contributors for use of their images:
Acalypha hispida, Kell
Acalypha pendula, htop
Acalypha wilkesiana 'Dubai' by Chamma
Acalypha with red leaf by htop
Euphorbia umbellata 'Ruby' by happenstance
Ricinus communis 'New Zealand Purple' by onalee