You can divide it but I'd wait until Spring. Some osteos don't like the cold.

You might like to take some cuttings as backup just in case.Funny time of year to do it but they do root easily.

BTW the plant is an Osteospermum - no 'n' :)

Division may be problematical, since Osteos don't produce shoots from underground, like Mums do. The lower branches often root, but that's not a sure thing. Cuttings are usually easier than dividing.

Thanks everyone. If I halve the plant (in spring) will it survive? I will take cuttings but haven't got any room to put them at the mo so it will gave to wait till spring. Colder week forecast with ground frost here in Shropshire.

Why not wait until spring and then just cut half of it off without disturbing the roots?
You could take cuttings from the half you cut off. Win win.

Good idea Steragram, thank you for your sensible suggestion!

my osteo has a single stem that is rooted so I wouldn't be able to split it. I take cuttings every year in September to be sure to keep it going.

Another way and well worth trying is to peg some of the straggly bits down then cover them over with soil leaving the newest leaves showing, firm it into place, hopefully by the springtime it will have formed new roots, you can then cut away from the mother plant.

Irish mans cuttings!

Never heard them called that Mg, all I know is that it works with lots of plants and shrubs , so therefore worth a try.....

Definitely worth a try Lincslass!