Carmen Breton’s strange crested euphorbia with its green stems and leaves. Photo: Carmen Breton
Question: Several years ago, I received what I thought was a cactus as a gift. Apparently, it’s actually a euphorbia.
It has barely grown at all in all that time until last January when a radical change occurred. It started to produce green branches from base with big green leaves. It’s really very weird. Is this common? Everyone who sees this plant is really amazed. I’ve been calling it “Miss Bizarroid”. I’ve sent you a photo.
I wonder if I should transplant it or continue to water it every now and then as I have since received it.
Carmen Breton
Answer: Your euphorbia (yes, it is indeed a succulent euphorbia, not a cactus) is actually a grafted plant. There is a crested variety on top and a plain green rootstock underneath.
The grafted plant is a variegated crested euphorbia (Euphorbia lactea cristata ‘White Ghost’), an almost albino clone, hence its whiteness, which grows in a fan shape called a crest or a cock’s comb. It’s hard to root on its own, so it’s grafted onto an easily rooted upright green euphorbia, the oleander leaf euphorbia (E. neriifolia). So, in fact, you have two plants in one.
What happened is that the rootstock (the green part, E. neriifolia) has started to produce branches. This is not at all rare. Rootstocks of grafted plants often start to produce branches eventually or even offsets (baby plants from the base).
Obviously, since the branches arise from the rootstock (E. neriifolia), the stems are green and leafy like it. They show no signs of crested growth or albinism.
To Maintain Your Plant’s Crested Character
People grow variegated crested euphorbias for their frankly weird crested growth, like brain coral. So the last thing you’ll want is to see that growth hidden from sight. Yet the oleander leaf euphorbia is a big plant, a succulent shrub with large green leaves. If you let the green branches continue to grow, they’ll grow taller and denser, hiding the crest from view and, indeed, will likely eventually smother the crested part.
If you want to maintain the crest, you’ll therefore have to remove the green branches. And that’s very easy to do. Just take a pair of pruning shears and clip them off where they join the stem.
Do so wearing gloves and eye protection, as the milky white sap of E. neriifolia is toxic. It can irritate the skin if you don’t rince it off. Worse yet, you don’t want to get any in your eyes, as euphorbia sap in an eye can cause extreme pain and even temporary blindness.
Basic Euphorbia Care
After pruning, continue with your usual maintenance of good lighting, normal indoor temperatures and watering only when the soil is dry to the touch. Since the crested part of the graft is very, very slow growing, it will need little or no fertilizer.
Answering your question, yes, you can repot your grafted euphorbia, ideally in the spring or early summer. That would be wise, because, according to your explanation, it has been in the same soil for several years now and any soil starts to become a little toxic over time because of the mineral salts which accumulate in it.
Also, from the look of your plant, it seems to be one of those that has a glued-on pebble mulch and no drainage hole, something that is not good for the plant. Ideally, you’d remove the mulch and place the plant in a pot with a drainage hole. You’ll likely have to break the pot with a hammer to extract the plant.
Remember though that the purpose of repotting this kind of crested plant is to replace the contaminated soil with fresh soil, not to enlarge the pot. Since the plant’s growth is almost zero, it will likely never need a pot bigger than the one it has right now. Putting a limited root system into a large pot is likely to lead to rot.
And, of course, also remove any new branches that the rootstock may produce in the future as soon as you seem them.
Best of luck!
This happens often with citrus, particularly the slow growing types. Kumquat trees can unexpectedly producing humongous and lumpy yellow fruit on wickedly thorny and vigorous stems, which is really that of the shaddock understock.