The only reason you might do some root pruning, and I certainly wouldn't, too skilled for me, is if you want to keep the plant in a pot that its now too big for. Otherwise, they grow perfectly well in open ground or in a pot, so long as you pot on when necessary.

Thanks Bamboo. The rosemary will stay as it is. Not too big.

I think you have to accept that these lovely plants, whether in a pot or in the ground have a point past which it isn't worth keeping them (after quite a few years), as they can get so woody and leggy, and pruning of any sort isn't going to help. I take cuttings from mine (very easy) every year so I have a succession of growing plants to take over from the oldies. I've never thought of root pruning - far too technical, I would have thought. I'm with Bamboo on this one.

Thanks Gattina. THe plant ahs been left as it is.

Root pruning is somewhat risky on a rosemary, anyway, since they are likely to resent it.

Thanks Tugbrethil. Definitely will avoid it.