This little shrubby plant shows up everywhere in our yard. I don't know if it was planted by previous owners of the house or if it is a wild species. It looks a bit like boxwood, and I'd like to know about how I should prune it.

It is low growing, maybe 18 inches at its tallest, with long arcing branches.

The climate here is similar to zone 9 in the US, with a bit of winter but the ground does not freeze,

Thanks for any suggestions.