I have a Euphorbia trigona houseplant which is about 6 feet tall and quite thin. It has gotten weak and is bending. It looks like it is going to break. I have read it can be propagated by stem cuttings. I don’t know if this means cut the end off OR cut several sections of the stem. If I just cut off the end will the original stem survive?
According to Indoor Gardening by Kate Jerome (Pantheon Books, 1995), Euphorbia trigona often becomes top-heavy, which sounds like what is happening to yours. They do tolerate pruning well and may branch out from the place where you prune. Do be very cautious in handling this plant, and be sure to wear gloves: it has a toxic sap that can cause skin irritation. Generally when cuttings are taken, they are from the tips, where the new growth is occuring, but you can also try several cut pieces of stem. Ordinarily not every cutting is able to form roots, but according to The Complete Houseplant Book by Peter McHoy (Smithmark, 1995), you can increase your chances of success by letting the cut ends of the stem dry out in the air before putting them into potting soil.