Boxwoods can take some pretty extreme pruning. Opening the shrubs up for more light and air flow is exactly what's recommended to rejuvenate these shrubs. If I were working with a small number of boxwoods and had plenty of time, I'd hand prune each tree, but with 500 shrubs, that doesn't seem like a real option. I think your boss's plan, from the way you describe it, sounds right on target.

I'd prune them in early spring just before new growth begins, but they'd probably be fine if pruned just about any time. Pruning in late summer/fall should probably be avoided because new growth can be sensitive to cold weather.

From Virginia Tech: Virginia Cooperative Extension. Good website "Boxwood in the Landscape" just by Googling pruning boxwood. Check out the Nat'l Arboretum's site "Thinning boxwood" on the same google page (has pictures). Books on pruning abound but lots of the same info is on the net.

"Shearing and Pruning
Shearing is the uniform removal of all or part of the latest flush of plant growth. Plants are sheared to increase compactness or to maintain a specified size or shape.

During the first few years after planting, boxwoods should be sheared after each flush of growth to encourage additional branch development. Thereafter, they should only be sheared to maintain a desired shape or form. However, be aware that continuous shearing causes a thick outer shell of foliage that creates dense shade on the interior branches. Continuous shading of the inner branches results in foliage drop from those shoots, thereby decreasing plant value and aesthetics. Do not shear boxwood in late summer since this might force new growth that will not have sufficient time to harden before frost.

Pruning is the removal of selected branches or plant parts. Plants are pruned to remove diseased, injured, dying, or dead branches. Unwanted branches are also removed by pruning, especially when plants are being trained to a specific form, such as a topiary or espalier. Boxwoods are best pruned, rather than sheared, to maintain a natural shape and to keep plants at a desired size so that they do not outgrow their landscape value too quickly. Boxwoods usually require some pruning in spring to remove any branches that have been killed during the winter. Also, as plants get older, some of the older branches may have to be removed so that light can get to the inner shoots."

Wait till spring - forget the hedge trimmers and go with a pruning saw or good pair of bypass pruners to take out any damage or selected overgrowth. Boxwood can pretty much take whatever you throw at it provided it's the right time of the year. Living in Maryland for 30 some years, I've dealt with lots of boxwood - hedges, freestanding specimens, the whole nine yards and am delighted we're getting some varieties here that can withstand Zone 4 conditions.

It's also recommended that you make the top width of your shrubs somewhat narrower than the bottom so that light can reach all the branches of the shrubs. You COULD go ahead and get to work on them now without doing undue harm, but, if you are cutting them back drastically, to the point of cutting off alot of foliage, you don't want that bald look to last any longer than necessary, so wait until you start to see new growth happening. Then get to it.

If the boxwoods "have been neglected and have out grown their spaces", lightly trimming them so as not to have a bald look for a while may not really be an option. If the trees had been maintained over the years, then a more maintenance type of trimming would be in order. In this case, it sounds more like a rejuvenating type of pruning is in order. I've seen large boxwoods pruned as the original poster said his boss recommended. They may look a little pitiful for a while, but they recover and reward the effort with thick full healthy growth. I doubt satisfactory results will be gained unless a rejuvenating pruning is performed.

Thanks for the help everyone I feel I have a much better understanding of what to do. I did check out the VT site as well as the National Arboretum site ,both were helpful. Well off I go with my pruners. Lynn