This is probably a very basic question, but I'm a gardening novice and need your advice. I've recently purchased a house in London that has the typical small hedge in front of the house for privacy. The previous owner neglected the hedge for some time and it has grown over the sidewalk in a round bulbous fashion....very unattractive! I would like to trim it back but need to cut back at least 1-2 feet to get it back to a nice and tidy size. However if I cut back that much I will have cut off most of the greenery - does it grow back in spring? I've purchased an electric hedge trimmer and am ready to go, but can I take such drastic measures all in one go or do I have to gradually prune back over time?