Not a second crop, just better bloom the following year.

For maximum flower production, pinch off faded flowers or the developing seed capsules that follow [deadheading]. Most successful rhododendron gardeners do not deadhead. It is not because they don't believe in it or that they don't want to do it, but rather because they have so many plants and so many other more important tasks that they don't have time to do it. Does this cause a problem? Not really. Some plants that are reluctant to bloom or have disease problems such as petal blight or in an area that is marginal for the plant in question may benefit from deadheading, but that is unusual.

thanks