First we get the question, trimmed for space.

Q: Hi there,
Just wondering if you could give me some pruning advice…. Euphorbia candelabra on her terrace… overlooking the River Thames… too big for the space….

Is it possible to prune it back? One of the cactus experts at the Hampton Court Flower Show here told me it would die if I did so… it will have irritating sap…

Any info you could give would be much appreciated. I don’t come across many outdoor cactus here in London, usually just red geranium and buxus balls and so could do with a bit of your much more expert guidance.

Look forward to hearing back from you

Best Regards
Elle

Then we get the compact answer:

Elle,

Yes, you can prune the Euphorbia, if it is done right it will not kill the plant, but it will cause them to scar and then branch over the next few years. You should prune now during warm weather so it has a chance to heal before your wet and cold winter. It should be easy to cut with a pruning saw or a serrated knife. The sap on Euphorbia candelabra is very toxic so make sure you wear safety glasses or use a full face shield, chemical resistant gloves and long sleeves. You do not want the sap in your eyes, as it can cause blindness! To stop the “bleeding” use 3% Hydrogen-peroxide from a druggist, put in to a spray bottle and spray the cut heavily as soon as you are done cutting. It will make the sap stop flowing fairly fast, but watch for splatter while you spray (a real good reason to wear a face shield).

Good luck (and we would love an emailed photo of a before and after to put up on Cactus Blog).

Hap