'Lee's Dark Purple' is one of the oldest of the fairly hardy, so-called classic rhododendron hybrids; it has been, and still is, extremely popular. Its popularity is based on the startling dark violet blooms in fully round trusses. The hybrid is a descendant of the Catawba Rhododendron (R. catawbiense). It has been speculated that it comes from a cross with the Great Laurel (R. maximum), but there is no clear evidence of this.
The shrubs grow to about 1.5m in 10 years unless depressed by the snow, as has happened at Mustila. On the other hand, these creeping branches are well protected from severe frosts. Light conditions also affect the habit: in shade, growth is stronger and the shrub is less compact than when growing in half shade.