R. stenopetalum ‘Linearfolium’ at Biltmore Estates in Asheville, NC

Although rarely seen, spider azalea (Rhododendron stenopetalum  ‘Linearfolium’) will be a pleasing addition to your woodland garden (USDA hardiness zones 6-8). Few people would ever guess that it is an azalea. This airy shrub grows 3-4 feet tall and a whole lot wider. It is slow growing, but is worth the wait. This unique semi- evergreen azalea hails from Japan.

April blooming spider azalea.

The very narrow (ribbon-like) leaves of spider azalea are mostly deciduous, nearly 3 inches long, and crinkly textured.  The pink April/May flowers are very spider-like and appear in terminal clusters of three. Flowering may last 4-6 weeks in a dappled shade garden locale and are lightly fragrant up close.

Flowers are unique in that the  1 1/4 inch-long pink sepals tend to be slightly larger than the pink petals. Flowers are borne on tips of branches. The overall shrub is finely textured and will catch the attention of friends and visitors to your garden.

Spider azalea thrives in cool shade, best in partial day sun, preferably in the morning. Roots demand a moist, humus-rich, well drained, acidic soil and high shade that permits filtered sunlight. Do not plant in deep shade. The foliage is easily harmed by dry winds.

Feed spider azalea at the same time as you fertilize other azaleas and rhododendrons — once annually in late winter or early spring. Use a slow release fertilizer such as Osmocote™ or Nutrikote™. Maintain a 2-3 inch layer of an acidic based mulch comprised of pine needles or pine bark chips. Pruning is rarely needed and performed to shape the plant or to remove a dead or broken small branch. Irrigate as needed the first year to establish new shrub. Disease or pest troubles are rarely seen.

A number of sources, including Niche Gardens in Chapel Hill in North Carolina and Woodlanders Nursery in South Carolina, NC, list the variety ‘Seigai’.