Azaleas and Rhododendrons

It wouldn't be spring without mention of rhododendrons and azaleas. Few flowering shrubs provide such vibrant spring color in shady gardens. March begins the planting season for milder regions in the south and west, and for central and northeast regions, it's time to begin preparing for the planting season by reviewing some quick tips for creating colorful azaleas and rhododendrons.

Azaleas and rhododendrons are closely related plants in the genus Rhododendron. There are hundreds of species and varieties to choose from so it's important to select types that are well-adapted to your garden environment and local climate. Your local nursery or garden center is your best source of information on adaptation of different varieties.

Rhododendrons

Rhododendrons are evergreen, taller than azaleas and have large, leathery leaves.

Growing Environment – Plant in shady areas. Rhododendrons are widely adapted to grow in all regions of the U.S. except areas with extreme summer temperatures or very cold winters.

Ideal Soil – Highly organic, acidic and well-drained.

Blooms – Large flower clusters are born at the end of the branches in early spring, primarily in shades of white, pink, red and purple. However there also are varieties with yellow, orange and salmon colored blooms. In ideal conditions, rhododendrons can grow into large trees, but most garden varieties stay in the five to 10 foot range.

Azaleas

Azaleas tend to be smaller, compact, spreading plants with tiny, evergreen or deciduous leaves.

Growing Environment – Best to plant in shady areas but some varieties can take more sun. Azaleas are more widely adapted to warm summer temperatures than rhododendrons and can grow in all regions of the U.S. except the desert southwest and areas with very cold winters.

Ideal Soil – Highly organic, acidic and well-drained.

Blooms – Most azaleas completely cover themselves with early spring flowers in almost every shade except blue and green. They usually grow three to six feet high. Some deciduous types have good fall color.

Soil Preparation

Azaleas and rhododendrons grow best in moist, acidic soil with light shade, although some types take more sun than others. In alkaline soils leaves turn yellow and have scorched edges. Consult your local garden retailer or nursery about soil testing kits best suited for your needs.

Tips for Planting and Caring for Rhododendrons and Azaleas

• Choose a planting site with rich, well-drained, acidic soil.
• Plant in area with light filtered shade. Avoid hot, dry or windy sites.
• Before planting, generously amend soil with organic matter, such as compost. If it's too alkaline for azaleas and rhododendrons, amend with sphagnum peat moss to increase acidity, or plant in raised beds or containers.
• Plants will succumb quickly in poorly drained soil. Check drainage by filling the planting hole with water, let it drain and fill it again. If the hole doesn’t drain overnight, it is best to plant in raised beds or containers.
• After planting, apply a thick layer of organic mulch and keep soil lightly moist, never letting plants dry out completely.
• Continued care for your azalea and rhododendron includes fertilizer and insect control. Try Bayer Advanced™ All-In-One Rose & Flower Care Concentrate to fertilize and protect.

Products Mentioned In This Article

All-In-One Rose & Flower Care Concentrate