Flower colors are variable, mainly shades of yellow, orange, and red. The mature height and spread of the mollis azaleas is approximately 6 to 8 feet. When planting rhododendrons and azaleas, proper site selection is extremely important. Azaleas prefer partial shade to full sun. Densely shaded areas are poor sites for azaleas.
Rhododendrons grow best in partial shade.
Areas that receive filtered sunlight throughout the day or morning sun and afternoon shade are good sites for rhododendrons. The evergreen rhododendrons often suffer extensive leaf burn during the winter months when grown in sunny areas and windy, exposed sites. The winter sun and northwest winds dry out the foliage, causing it to curl and turn brown. Rhododendrons and azaleas, members of the Heath or Ericaceae family, require well-drained, acid soils with a pH of 4.0 to 5.5 for best growth. The pH of most Iowa soils ranges from 6.0 to 8.0.