Department of Horticulture New York State Horticulture Study Guide for Youth 4-H Logo


Flowers &
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Cornell University

Azalea or Rhododendron
Rhododendron sp.

Click on thumbnails for larger image.

What about it?

Rhododendrons are large, broadleaf evergreen shrubs native to North America and Asia. In a cultivated environment, many will grow up to 6 feet but have the potential to grow to 15 feet or so. Rhododendron leaves have a rich green color and a smooth, glossy texture. The flower buds of the rhododendron are large and pointed and emerge in clusters. Depending on the variety, rhododendron flowers can vary from pale pink to purple, yellow, orange, red, and even white. Blooming usually occurs sometimes in May or June. A few species, such as Rhododendron vaseyi have the additional benefit of having red foliage in the fall.

What is it used for?

The handsome rhododendron shrub is quite popular as an ornamental. It can also be used as a border plant.

Where does it grow? How do we grow it?

The rhododendron prefers partial shade and moist, well-drained, acid soil. It grows best in a soil that is high in organic matter. Use your compost! And when planting, give each rhododendron at least 6 feet of growing room.

What are its primary problems?

Rhododendrons have very specific site requirements which might make growing them a challenging task. Be wary of severely cold weather and alkaline, iron deficient soils that will damage the flower buds and discolor the leaves respectively. Rhododendron borers, canker, and wilt also pose a threat and deer are quite fond of rhododendron buds, leaves, and stems.

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Copyright, Department of Horticulture, Cornell University.