I'm in Toronto, zone 6. I don't need help so much as learning when is a good time to trim boxwood.

If flowering is not an issue - and it is not with a boxwood - then pruning broadleaf evergreen shrubs is suggested in very early spring, just as the plant is pushing new growth. You can also do it later if you wish but now is a bit too late :-) August 1st is typically the cut-off date for colder climates.

bingo ... you want it slowing down into dormancy ... not getting all excited and reflushing this late ..... and then being hit with a hard frost or freeze ... in other words.. it wouldnt be properly hardened off ...

ken

And they don't need acid soil. They're tolerant of wide range. The eponymous Box Hill in southern England, named for its ancient native specimens, is on chalk down land.

Thank you to all of you. Mine are in clay soil, I add compost and sometimes coffee grounds. Strangely, I've got information that boxwood needs acidic soil! Good to know. I'm curious, what do these ancient native specimens look like compared to present day boxwood. I have seen so many, starting in my home country, to seeing some old varieties in older gardens in Toronto. Different shapes, foliage, growth pattern. I appreciate mine in the winter, some don't do well, while others seem untroubled by snow.