Pruning to make bushier annuals.

I have some non-trailing lobelia, petunia and nemesia plants for bedding out, and wondered about pruning them to make a more bushier plant with more flowers, particularly with the lobelia that is really getting long growth on it. What do you think as I have heard of it but never tried it before. I  know it will delay the flowers but may get a better performance from them, plus they may not grow as tall.