"Cambridge Scarlet" Bee Balm grows about 3½' tall in my garden.  The leaves smell nice and minty when rubbed between the fingers.  It's worth growing just for that reason!  The flowers attract swallowtail butterflies and hummingbirds.  The plants also attract earwigs and Asiatic Garden Beetles, which devour the petals and leaves.  Because of these pests, my plants are usually void of flowers.  However, 2004 was virtually a pest-free year, and my Monardas had flowers on them from late June right up to October.  Bee Balm spreads by sending out shallow roots in all directions.  Some gardeners plant theirs in bottomless containers sunk in the ground.  I have tried that and found it to be too much trouble.  I contain my plants by regularly pruning the roots with a flat-blade shovel, and removing the pieces.  Powdery mildew is a regular problem for bee balms, but can be avoided by purchasing mildew-resistant varieties.