Depends on the variety of euphorbia - the herbaceous perennial ones can be divided in spring or autumn. Evergreen hardy ones can be propagated from semi ripe cuttings. Most will grow from seed. One or two other varieties have a woody central root, and that can be cut in half and replanted.

Some of mine self sow but the seedlings won't necessarily be the same as the parent

So much to learn.........!

Be careful not to get the white sap of euphorbias on your skin. It is poisonous. Some euphorbias have sap deadly enough to have been used on poison arrows! There are many euphorbias some much more poisonous than others

http://www.theamateursdigest.com/epoisons.htm

Note: when taking cuttings of Euphorbias, it's a good idea to have a cup of semi-hot water--about half way between baby bottle and a hot cuppa--to dip the cut ends in and stop the flow of the milky sap. That makes it easier for the rooting hormone to stick to it, and speeds up the new roots all by itself.

I didn't know that, Tug - what a good idea. Do you have any idea how long the cut end should be held in the hot water for? Thank you, everyone for your answers.

It usually just takes a couple of seconds to coagulate the latex, Gattina.

Thx, Tug