It is obvious that close planting [of shrubs] gives a furnished look to a border almost immediately, equally obvious that it is wasteful and expensive.
The Well-Tempered Garden by Christopher Lloyd (1973).
Dead heading rhododendrons
The usual advice is to dead head all rhododendrons. In fact, while they all look a great deal better for dead heading, it is really only necessary to do the ones that set seed. You will be able to tell by looking, if you didn’t do them last year, because they will have spent pods similar (but almost certainly smaller) to the ones shown in the photo. Some rhododendrons can set so much seed that they weaken themselves and eventually die. My neighbour swears by coating his fingers in olive oil before he goes out to dead head. It stops the gunky residue from making your hands sticky.