Purple Gem is the most drawf offering of our rhododendron. It's leaves, flowers, and growth style is more like a drarf azalea than a traditional rhododendron. Purple Gem is very handsome when kept trimmed and planted in well drained soil.
Be sure to use a well drained soil medium when planting any Rhododendron as they prefer fall planting with less watering than you might think. In NC our soil is clay so we prefer to use pine bark soil conditioner when planting Camellia, Rhododendron, Mountain Laurel, and Azalea.