Question
When is the best time of the year to trim shrubs and evergreens?  I live in suburban Detroit area.  When I trim them now, the cut areas seem to brown over.

Answer
Roy,
If you are pruning with a hedge trimmer, then you are doing damage to the leaf tissues that are remaining. This is what is causing the browning.
Evergreens and other shrubs, as long as they are not the flowering type, can be hand pruned at any time of the year. Flowering plants should only be cut back immediately after they are done flowering.
Good luck.
Ed Gulliksen