How to trim overgrown Juniper Shrubs?

I have 4 or 5 large rectangle Juniper shrubs in the front of my house lining the gr area, however, they are now overgrown to the point where they cover the sprinklers entirely. I would really like to take some hedge trimmers and trim them back but also don't want to be left with dead brown Junipers. Never had to deal with these plants before...there are also sections that almost look like they are "falling over". I also have Juniper trees that constantly have leaves falling over. I cut them off but then it exposes the brown area and I hear that doesn't grow back. Any advice would be appreciated!!