Rhododendron-Facts and Care

Rhododendrons are gorgeous flowering shrubs that can be grown easily. Rhododendrons can, however, be a a little tricky to grow if you choose the wrong variety for your growing zone. Find facts and information on growing and caring for rhododendrons.

Rhododendron Facts and Info

Rhododendrons are members of the Ericaceae family, which also contains rhododendrons, as well as Azaleas. The two vary greatly but have some similar traits. Here's a saying you might have heard, " Not all rhododendrons are Azaleas, and not all Azaleas are Rhododendrons". Is this confusing? Rhododendrons come in a variety of forms as well as variations.

Some may grow into trees, but most of them are small bushes or low growing shrubs. Some rhododendrons are suitable for rock gardens, some are even epiphytes (non-parasitic plants which grow on other plants, deriving their moisture from the air). You will be able to grow beautiful plants by simply learning about rhododendron care.

Rhododendrons come in many colors

Flowers and Choosing Varieties

The flowers on this plant come in actual clusters of many flower blooms. It's foliage is elongated and makes a great specimen plant. Each species varies somewhat as to colors of their flowers, height, and foliage. Some of them produce leaves as long as 24 inches, others have tiny leaves barely an inch long. When they are flowering, some are tubular, others are saucer-like, and still others are nearly flat.

The Rhododendron is a beautiful shrub, but the only problem is, finding a variety that will grow in your climate. This is the limiting factor to growing these plants. The thrive best in a moist, temperate climate where the heat of the sun is often tempered by cloudy skies, such as the Pacific Northwest.

They are easily grown along the sea coasts, but they are not recommended for amateur gardeners in the central portion of North America. There are , however, small mini-climates in every section of the country. Rhododendrons grow in many parts of the country where, even I, was surprised to see them growing.

Growing Rhododendrons

If you would like to try growing rhododendrons, make sure you plant them in full sun, provided that they have enough moisture and are shielded from windy conditions. If you live where the summer is really hot, you will want to plant them in the shade. Usually the large leaved varieties prefer the shade areas. Their leave will burn if exposed to too much light.

If possible, you might want to naturalize them in a woodland setting. If this is not possible plant them in a Northern location, or even a northwest or western exposure. Southern exposures are definitely a no! Remember that exposure to strong light in winter is even more harmful than in summer, because it is then that serious scorching of the leaves occur.

Check the Acidity of Your Soil

Soils for rhododendrons must contain an abundance of organic matter. They dislike lime and will not thrive in soil where it is present in any quantity. They are much like azaleas in this respect. It might be a good idea to take a soil test to determine the acidity of your soil before you even purchase your plants. Soil test can be purchased from retail stores or hardware stores and are usually very easy to use. If you have lime present, dig out the soil and replace it with soil that is acid or neutral. The addition of rotted compost or well-decayed manure will help, along with acid peat moss.

Rhododendron Care

Rhododendron Ponticum

Rhododendrons are shallow-rooted, so the surface of the ground should not be cultivated, as digging among the roots will harm them. Mulch well to keep down weeds, using leaves, peat moss, pine needles, or even sawdust. Water them well, especially when the weather turns warm and dry. You should water them thoroughly once a week, especially in late summer and fall in regions where rainfall is very low.

Fertilizing is not necessary as long as the plants maintain good growth, but as they grow older and use up the nutrients in the soil, it is a good idea to add some well-decayed manure or some type of complete fertilizer recommended for acid loving plants.

Prune them only if it is necessary to maintain plants of well-balanced growth. Remove all of the old flower heads promptly before the seeds form on them.

Winter protection is only necessary where winters are extremely cold. Do not use tight fitting barrels or boxes to protect rhododendrons because they don’ t need warmth, they just require shade and good circulating air.

What causes Rhododendrons to die?

As is the case with most plants, the top cause of death overwatering, or not watering them enough, or applying too much fertilizer, or if you plant them in areas where it is too cold for a particular variety to grow.


The selection of rhododendrons should be based on where you live. Sizes of rhododendrons range from 18 inches to tree size. There are dwarf varieties, hybrid varieties and species rhododendrons. There is a list of many of the favorite varieties of the American Rhododendron Society members that is listed by the states that might be very helpful.

New varieties that  you might want to consider

Cherry Cheesecake Rhododendron, Kabarett Rhododendron, Brechtbill Rhododendron, Fir Rim Rhododendron, Hotei Rhododendron, The Honorable Jean Marie de Montague.

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