The answer to that question is simple. Yes. You should wear both a pocket square and a boutonnière at your wedding, but only if you are the groom.
Keep the boutonnière super simple so as to not over power the bride and her beautiful bouquet. However, your best man and groomsmen should not wear a boutonnière. Think of the photos. You don't want all of your men looking overly flowery in all those pictures. A simple pocket square and some sort of necktie or bow tie will do the trick for them. But if you are the groom, feel free to go for both a boutonnière and a pocket square along with your necktie or bow tie. Below are a few excellent examples of boutonnières and pocket squares worn together. We hope this helps!
Photography by Lost In Reverie Photography.