How do I control/prune runaway growth on my Rhododendron bushes?

Rhododendron should be pruned right after flowering.Do not over prune that will send the bush into shock

during or immediately after blooming. Remove what you do not want

Sprinkle coffee grounds around the plant. Snails and slugs don't like it on their bellies. As above, sand would probably work and I've heard beer works, too. Good luck.

I purchased a Mobile Home in Fl.....that had Rhodi in back yard that had spread to about 20' across and was easily 12' tall. I thinned and removed all sorts of trees growing in the zone in early spring as it didn't have much in bud. The second year I pruned about a third in height right after blooming and cut back some of the offspring that was creeping outwards in all directions. Fertilize and watch it bloom the next year. It's work, but well worth the effort.

While it's blooming or RIGHT after would be ideal!

Early spring or right after they bloom and the flowers are dead.