Rhododendrons: Planting requirements

I have been gifted with five Rhodos. I have never planted these before. Two are "Purpureum Elegans", are about 2 1/2 ft tall and very dense and bushy. One is called "Unique" and is about the same size as the first mentioned. These came in 5 gallon pots. I also have two red - not sure of the name - no tag. These came in a 3 gallon pot and are not as tall or as bushy as the other three. I would like to plant these under a mature maple tree, which has loose soil (unlike the rest of the yard - clay). Last year I dug up alders and added compost. This site faces south and will have dappled sunlight.
Can you provide any advice about planting and spacing, pruning, etc?? Thanks.

 

Can't say about the red but other two will get quite large so plant at least 5ft apart. Maple has shallow roots and may compete with the rhodo roots so I can't say that is the best place to plant ... but you are right in that clay probably isn't better. I have quite of bit of clay but the rhodies are in raised (non-clay) beds. Anyway, good luck...