Osteospermums can be cut back as they are quite tough, I believe. You have nothing to lose by trying to split yours though since you'll still have half of it left if for some reason it takes offence at your treatment.

It should be fine,Harry..we had these to fill gaps ,in a new border,but they can get out of hand ,and look untidy..I did the same as you ,and dug parts of them up,no problem..I only have one now,which is also growing over a path,but I just trim it backand .it still flowers well,13 years on ..Also,a good idea to cut off the dead flower stems ,to keep it looking tidy.It should keep on flowering well into late Autumn..

Hello Arbuthnot and Bloomer, thank you both very much for taking the time to get back to me, I'm going to attack and trim tomorrow morning and follow both lots of your advice. How far would either of you cut these back in late Autumn, keeping in mind I want my Osteospermums to get bigger the brighter each year.

You only need to give it a tidy up,Harry,and take any tired looking foliage and dead stuff off....Next spring,you can decide if you want keep it as it is,or split it again..so a good trim tomorrow will result in fresh healthy growth..good luck :o)

And when you trim them remember that cuttings root very easily - use green shoots rather than old ones.

Thank you Bloomer and Steragram, I do love Osteospurmums, very grateful for your advice.

Anytime,Harry..there is always someone who will try to answer your questions...