A few weeks ago a friend asked me for advice on a new houseplant she had received as a gift.
"It's called a Coral Cactus," she said, "and it's absolutely beautiful. But I don't know how to take care of it."
I had never heard of this plant, but then, the trends in houseplants have changed a lot since I collected them more than 30 years ago. So I looked up as much information as I could find and gave her some printed sheets about the care and management of this plant.
All of this happened within a few weeks and it wasn't long after that I heard the plant had died. I felt bad for my friend, especially since the plant was a gift, but a little angry that these, for lack of a better word, "Franken-plants" are being sold to customers who are unaware of exactly where their money is going.
Coral cactus is not a cactus. Like other plants mistakenly called cacti, it is a Euphorbia, and although that sentence spoke of the plant in singular, it is actually two different Euphorbias, one grafted on top of another. The top part of the plant, Euphorbia lactea, also known as mottled spurge, is a common houseplant that produces a coral or crest-shaped bloom that is often quite colorful.
The bottom part of the plant, which the frilly-shaped flower is grafted onto, is another species of Euphorbia, E. nerifolia, a larger, stronger species that has a sturdier stem and root system.
That is not to say you shouldn't buy this plant if you find one. They are lovely to look at and can help bring color to an otherwise dreary, gray winter. But there are basic maintenance issues that should be known to make sure the Coral Cactus will thrive and survive for many years.
Coral Cactus is a houseplant. Like all houseplants, it can be safely grown outdoors in climates much warmer than ours, so even if the plant is placed outside during the summer, it has to come indoors for the winter.
Although this plant prefers partial to full light, it should be protected a bit from the hottest mid-day sun by placing it where it can get bright or filtered light. Once the plant is brought indoors for the winter, it should be acclimated to the brightest window by first placing it in a low-light situation and then gradually moving it to higher levels of sunlight. The brightest winter light comes from the south, especially when that light is not filtered through drapes or curtains. Even plants that prefer bright light can suffer in a southern exposed window. The heat from the sun shining through the window glass can burn a plant's leaves. But when the light is filtered through a sheer or light curtain panel, it cuts down on the heat exposure while still giving bright light where it's needed.
Coral Cactus is a Euphorbia, which although is not actually a cactus, it still retains water in its stems and leaves. These plants don't need watering as often as non-succulent type plants, so it's best to let the plant completely dry out between waterings. Many houseplant growers use a wooden dowel or skewer to test the soil. Push the wooden stick down into the soil more than halfway to the bottom of the container and leave it there. Checking the stick every few days for moisture and water accordingly.
The only time the plant needs fertilized is when its actively growing, generally in the spring, summer and fall. In winter, when light conditions are less than ideal, the plant will rest and won't need fed. Watering will likely slow down at this time as well.
Probably one of the most important things to consider when purchasing this plant is that it will probably need repotted. Most decorative containers from the stores don't have proper drainage holes. The container also could be covered with colored foil as a decoration. Enjoy the decorations for a few days, but then unwrap the foil. Overwatering and improper drainage will kill this plant quickly.
Finally, another important thing to know about Coral Cactus is that this plant is poisonous. All parts are dangerous if ingested and the white sap that oozes from the stems and leaves can irritate those with sensitive skin.