Pruning Rhododendron hybrids
Most can tolerate pruning, but if it is a heavy pruning it is best in early spring. Summer pruning right after flowering is also an option, but not too late, otherwise there will be no flowers the following year.
Planting Rhododendron hybrids
All are planted in sphagnum for rhododendrons, they love a coarse sphagnum with air. All rhododendrons have a compact root, this means that a good sphagnum makes the growing conditions better.
Rhododendrons like fertilizer, they don't grow that much, but they have leaves all year round and therefore they actually use a lot.