Rhododendron Planting Tips

Rhododendrons are prized for their glossy foliage and large blossoms, which make them one of the most popular shrubs for backyard gardeners, according to the University of Missouri. With the right care during the planting process, a rhododendron shrub can become quickly established in your landscape and provide years of ornamental enjoyment.

Site Selection

Rhododendrons thrive in areas that receive light shade and are shielded from winds, according to Ohio State University. The university suggests planting them on the north side of a building, hedge or fence.

Soil Preparation

Rhododendrons require well-drained soil that is high in organic matter, according to Oregon State University. Mix in enough organic content, such as aged compost, to create a crumbly and loose soil texture. If the only soil you have is very heavy clay soil, Oregon State University recommends building a raised bed with imported garden loam or potting mix. Such raised beds should be a minimum of 12 inches in height, according to the University of Missouri.


Rhododendrons need adequate space. Crowding rhododendrons too closely to other shrubs may stunt their root development, which affects shrub growth and flower production. The University of Missouri advises spacing the plant a minimum of 3 feet from surrounding shrubs.


Gardeners usually buy rhododendrons in pots or in burlap-wrapped root balls. Oregon State University suggests digging a hole that is double the diameter of the pot or root ball and a couple inches shorter so the plant's base is slightly higher than the edges of the hole. This gives leeway for the soil to settle after planting. Otherwise, the plant will sink lower than the surrounding area.


Mulch helps conserve soil moisture and adds micronutrients to the soil. This can help the new rhododendron become established faster. The American Rhododendron Society recommends peat moss, decayed manure and shredded leaves as mulch.


Unlike many shrubs, fertilization at the time of planting is not recommended, according to the University of Missouri.

Soil Acidity

Rhododendrons require acidic soil and experience optimal growth in dirt that has a pH level ranging between 5.0 to 5.5, according to the University of Missouri. A pH testing kit available from most garden stores or nurseries will show you your soil's current pH. Soil that is too acidic can be made more alkaline by mixing in a limestone product, while soil that is too alkaline can be acidified by mixing in ferrous sulfate. The specific amounts of limestone or ferrous sulfate needed varies according to your specific pH and gardening space. Contact a regional cooperative extension office (see Resources) for site-specific recommendations on adjusting pH.

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About this Author

Josh Duvauchelle is an editor and journalist with more than 10 years' experience. His work has appeared in various magazines, including "Honolulu Magazine," which has more paid subscribers than any other magazine in Hawaii. He graduated with honors from Trinity Western University, holding a Bachelor of Arts in professional communications, and earned a certificate in applied leadership and public affairs from the Laurentian Leadership Centre.