To Plant or Not to Plant Rhododendrons

Rhododendrons are a relatively expensive plant to purchase and must be provided with special soil. Rhododendron maximum and Rhododendron catawbiense with their hybrids, represent one of our Hardiest broad-leaved evergreens. There are few other evergreen plants able to take low temperatures and still produce spectacular blooms in early May. They are also suitable for lightly shaded locations.

In order to decide whether to include rhododendrons in the landscape, examine their needs and decide if these can be provided in order to benefit from their beauty. Both the Catawba rhododendron (Rhododendron catawbiense) and the Rosebay rhododendron (Rhododendron maximum) are native American plants, being found most abundantly in the Smoky Mountains. The Rosebay rhododendron is the hardier of these two species, but its flowers are less showy. It is best used as a large evergreen plant for a background or corner where year-around display is needed from the plan rather than its flowers.

The Catawba rhododendron has been developed into many varieties, colors and forms. These are by far the most easily available and produce beautiful flowers on plants that are quite hardy. Just a few of the many hybrids and selections include: Album Grandiflorum, America, Atrosanguineum, Charles Dickens, Everstianum, Lady Armstron, Nova Zembla and Roseum Elegans.

Rhododendron plants are best suited under light to moderate shade, and should be located where they get at least afternoon shade,beginning at about 1 pm. They are excellent plants for the north or east side of buildings, but may be used in other locations. If they receive light shade from trees or other evergreen plants. Too much sun in summer results in excessive heating and drying which can cause plant damage. Excessive winter sun in late afternoon may result in leaf scorch.

Rhododendrons should be planted in a deep, organic, well drained soil. Clay soils should be heavily amended with peatmoss, leaf mold and sometimes coarse sand if better drainage is needed. If drainage in the area tends to be poor, rhododendrons should be planted in beds that are raised above the soil level by 8 to 12 inches. Rhododendrons need an acid soil. If in doubt, soil should be tested to determine its acidity.

These plants grow best with a soil pH of about 5, but can tolerate acidity ranges from pH 4.5 to 6.0. Rhododendrons have very fine, shallow roots. Do not cultivate them after planting, but mulch them with leaves, bark or other organic materials. Plant them with the soil ball slightly higher than the soil in line because settling may occur, and they should never be planted too deeply.

Summer watering is usually essential, especially during the first few years after planting. Their fine, shallow roots are easily damaged by excessively dry conditions. Mulch helps minimize the problem, but it is not a total solution during drought conditions and hot weather. Rhododendrons need little care once established. Little pruning is necessary, although flower heads should be removed after flowering is completed.

http://en.wikipedia.org/wiki/Rhododendron