There are entire books written about the hundreds of varieties of rhododendrons and azaleas available. The lists you will find here are simply to give you some ideas and to get you started. Rhododendrons have an amazing range of hardiness, whereas the azaleas are often lost when exposed to several days of 20 degree F temperatures. Check with your local nurseries for variety availability and for hardiness of whatever plant you are considering.
When using rhododendrons and azaleas in the landscape, keep in mind that they are shallow-rooted plants, much more so than most other woody plants. They need well-drained soils, and will do best in soils that are fertile and amended with lots of well-rotted organic material. Mulches also help these plants to establish themselves, serving to minimize soil temperature extremes and helping to keep soil moisture intact. Most varieties of these plants do well in partial shade. Few do well in full, hot, afternoon sun, or in areas where they receive reflected heat from walls or other structures. Place them where they will be protected from winter winds, which can cause leaf “burning” by dehydrating the foliage during periods of dry cold.
While the tendency is to select a rhododendron or azalea when it is in bloom, take the time to study the plant to see what other characteristics it has to make it interesting the rest of the year. These plants generally bloom for a month or so in mid to late spring. Then, for the next eleven months you have the rest of the plant to look at. Consider its form, shape, interesting leaves, and other characteristics to make sure the plant will be a valuable addition to the year-long garden.
The root weevil list is one designed to guide you in selecting plants that have some resistance to, or tolerance of, the leading insect pests of rhododendrons and azaleas. When selecting any plant for the garden, consider what sort of problems to expect, and also search for those plants that have some natural resistance to the pests that are a constant worry.
Some of the low-growing and spreading types of evergreen azaleas (a) and rhododendrons (r) can be used in the landscape as groundcovers. They bloom vividly from midspring until early summer, depending on your choice of types and varieties. When planning your landscape to use these plants, keep in mind that they are very shallowly rooted and should be mulched to keep the roots damp during the dry summer.
Coral Bells Azalea
Bow Bells (r)
Cilpinense (r)
Ernie Dee (r)
Gumpo Pink (a)
Hini Crimson (a)
Mother Greer (r)
Purple Gem (r)
Small Gem (r)
Carmen (r)
Coral Bells (a)
Flame Creeper (a)
Gumpo White (a)
Impeditum (r)
Ptarmigan (r)
R. keiskei (r)
Snow Lady (r)
Some rhododendrons and azaleas mature at heights of more than six feet. Do not plant these in front of your picture window, unless you plan to peek through the trunks or to hide the window permanently. These plants need to be used in background plantings, to accent a particular place in the garden, or be planted to provide a barrier of flowers (in late spring) and foliage. Pruning is not the answer to a badly placed plant. Plan ahead and make sure you know how tall and wide the plant will become in a reasonable length of time, and site it so you don’t have to worry about keeping it in bounds that are less than the normal growth parameters.
Aladdin (r)
Antoon Van Welie (r)
Cannon’s Double (a)
Fastuosum Plenum (r)
Lem’s Monarch (r)
Loderi King George (r)
President Lincoln (r)
R. occidentale (a)
Sappho (r)
Sunset Pink (a)
White Grandeur (a)
Anna Rose Whitney (r)
Autumn Gold (r)
Cynthia (r)
Golden Lights (a)
Loderi hybrids (r)
Mrs. G. W. Leak (r)
R. catawbiense ‘Abum’ (r)
R. Schlippenbachii (a)
Stewartsonian (a)
Taurus (r)
Take the time to visit local garden stores, herbariums, parks, and other places where lots of rhododendrons and azaleas are used in the landscape, and make a selection after observing many plants. These will be long-lived members of your landscape if you select wisely, short term vagabonds if you don’t.
People who try to grow rhodys in the Pacific Northwest know that the major problem, once they have overcome the climatic concerns and corrected the soil to an acid pH, are root weevils. The adult weevil notches the outer margins of leaves, usually beginning in late spring, then the larvae form girdles the trunk and upper root system during the winter. Between the two stages of this pest’s cycle, a susceptible rhododendron will look tattered and torn or die. If your garden seems to be a haven for this insect pest, try some of these varieties that have been found through careful research to not be as tasty to the weevil.
Control of the root weevil consists of several approaches, none of which seem to be entirely effective. That is why we have listed those above whose inherent flavors repel the pest. For those of you who already have weevil-ridden plants, spray in mid to late spring with acephate or other recommended pesticides. This is to try to get rid of the adults, which chew notches in the edges of leaves. Then, in early fall, apply a parasitic nematode (available at most garden stores and sold under several brand names) to the soil where you suspect the weevil larvae will be hatching. Then, in late winter reapply nematodes or apply an insecticide drench to the root area of your susceptible rhododendrons and azaleas. Good luck!
Both of these plants have members that are completely hardy to some of the coldest winters in the United States. Called “H-1 Varieties” in most nursery catalogues, there are more than forty varieties that can live through winters where the temperatures drop as low as −25 degrees F. Treat these with respect and plant them in a spot that will protect them from freezing winds, which are so destructive to their foliage, and in soils that are slightly on the acid side of the pH scale. If you do that for them, you will enjoy them forever.
R. catawbiense
Abraham Lincoln (r)
Apricot Surprise (a)
Casanova (r)
Chesapeake (r)
Exbury hybrids (a)
Henry’s Red (r)
Lodestar White (r)
Orchid Lights (a)
PJM (r)
Ramapo (r)
R. Yakushimanum (r)
Spring Dawn (r)
America (r)
April Rose (r)
Catawbiense Grandiflorum (r)
English Roseum (r)
Ghent hybrids (a)
Mollis hybrids (a)
Nova Zembla (r)
Pioneer (r)
Purple Gem (r)
R. catawbiense ‘Album’ (r)
Rosy Lights (a)
White Lights (a)
“I would like to convince many of you who may feel left out that you can grow rhododendrons in your climate. With careful moisture control, sufficient light, mulching, and proper protection, some species and various new hybrids can be grown in rather rugged parts of the country. An oasis of climate can be created artificially, making possible the use of rhododendrons. You can join the increasing number of rhododendron enthusiasts.”—Ted Van Veen, Van Veen Nursery, Portland
Not many of the rhododendrons or azaleas are fragrant; however, we have pulled together a list from the nurserymen who grow these lovely plants, and we think you will find some varieties that fit nicely into your planned landscape. Plant them where you can enjoy their fragrance as you walk by or as you pause to admire their blossoms.
Beaufort (r)
Countess of Haddington (r)
Exbury hybrids (some)(a)
Fragrantissimum (r)
Ignatius Sargent (r)
Loderi King George (r)
Martha Issacson (r)
Mother of Pearl (r)
Naomi (r)
Cadis (r)
Dora Amateis (r)
Exbury Parade (a)
Gold Western Azalea (a)
Lodauric (r)
Loder’s White (r)
Mission Bells (r)
Mrs. A. T. de LaMare (r)
Pink and Sweet (a)
R. Fortunei (r)
R. occidentale (a)
Snow Lady (r)
R. Calophytum (r)
R. luteum (a)
Sapphire (r)
Viscosum hybrids (a)
“Even though many varieties of rhododendrons and azaleas are extremely hardy and can be planted in the higher and colder gardening areas of this region, they do not tolerate alkaline soils. If your soil is neutral in reaction (pH 7) or on the alkaline side, incorporate copious amounts of peat moss and other acid-producing organic material into the planting area and follow with an annual application of garden sulfur to maintain the desired, slightly acidic, soil reaction.”—Gray Thompson, Extension Agent Emeritus, Milwaukie, Oregon
Ted Van Veen, noted author of rhododendron books, speaker, and owner-operator of Van Veen Nursery, provided this list. He calls it “a collection of twenty-five rhododendrons suitable for the milder climates of Pacific Northwest gardens, selected for variety of color and growth habit, and some with unique plant character.”
A lot of rhododendrons and a few azaleas will take considerable heat. However, they will only survive if you take care of other aspects of plant care, such as watering, mulching, and protecting against wind and direct and/or reflected afternoon sunshine. With a little extra care, these plants can become a part of your yard. The varieties listed below will be the more hardy types.
Albert Close (r)
Anna Rose Whitney (r)
Bravo (r)
Caroline (r)
Chionoides (r)
Cynthia (r)
Dora Amateis (r)
Gomer Waterer (r)
Jean Marie de Montague (r)
Madonna (a)
Mollis vars. (a)
PJM (r)
Anah Kruschke (r)
Blue Peter (r)
Butterfly (r)
Catawbiense Album (r)
Cunningham’s Blush (r)
Daphnoides (r)
Fastuosum Flore Pleno (r)
Hallelujah (r)
Lord Roberts (r)
Mardi Gras (r)
Nova Zembla (r)
Trilby (r)
“When we list heat-tolerant rhodys, we mean warm climates, not necessarily in sun. The amount of sun they will stand depends upon the climate in which you live. In no case do we mean the south side of a wall in Arizona.”—Harold Greer, Greer Gardens, Eugene, Oregon
The large flowering clusters and massed beauty are not the only enchanting parts of these plants. Many of them have foliage that is different from other plants. Some have the underside of their leaves covered with a mass of feltlike hairs called indumentum. The indumentum ranges in color from tan to brown and yellow. Or the foliage of some will be aromatic, thus giving the garden an unexpected fragrance. Here are some that will surprise you with indumentum or fragrance.
Atroflo (r)
Daphnoides (r)
Fabia (r)
Great Lakes (r)
May Day (r)
Noyo Brave (r)
PJM (aromatic)(r)
R. Fictolacteum (r)
Scarlet Wonder (r)
Sir Charles Lemon (r)
Bow Bells (r)
Dora Amateis (aromatic)(r)
Good Times (a)
Leo (r)
Mist Maiden (r)
Odee Wright (r)
R. Carolinianum (r)
R. Keleticum (aromatic)(r)
Sherwood Red (a)
White Dwarf (a)
Some plants must be sheared frequently to make them compact. Others grow in a manner that shows them off as being compact sorts of plants. If the gardener can select the compact types to use in those parts of the garden that demand a controlled plant growth, pruning and maintenance chores will be diminished. Here are a few to get you started.
Dora Amateis (r)
Gumpo (a)
Hino-crimson (a)
Impeditum (r)
Mardi Gras (r)
Mrs. Furnival (r)
Noyo Brave (r)
Ramapo (r)
Rosamundi (r)
Unique (r)
Girard’s Pink (a)
Hi Gasa (a)
Hinodegiri (a)
Lorna (a)
Mist Maiden (r)
Molly Ann (r)
Patty Bee (r)
Red Bird (a)
Scarlet Wonder (r)
Ward’s Ruby (a)
The optimum single time for pruning a rhododendron or azalea is immediately afer blooming. At that time you can prune back the terminal shoots to visible side buds, with assurance that the plant will have another set of blooms for the next spring. If you prune before the plants bloom, you lose that year’s flowers. If you prune too late it may take another couple of years to make growth and set a flower bud.
It is possible to have rhododendrons and/or azaleas in bloom from mid-spring to nearly mid-summer by selecting varieties with different blooming times. The following list is filled with types that bloom early, mid and late season. The entire flowering season can be made as long as three months by utilizing different varieties with overlapping blooming periods. There is such a wide array of both of these plants that the beginning gardener will be overwhelmed. Don’t select only on the basis of flower, but consider also the growing habit, the foliage type, the color and shape of the leaves, and the overall form of the bush. Much of the information in this list came from Ted Van Veen and Harold Greer, both rhododendron growers and hybridizers for many years.
Very early (late February and through March) |
|
Bric-a-brac (r) |
Cheer (r) |
Christmas Cheer (r) |
Cilpinense (r) |
Conemaugh (r) |
Coral Bells (a) |
Cornubia (r) |
Else Frye (r) |
Praecox (r) |
Rosamundi (r) |
Early |
|
Anchorite (a) |
Blue Diamond (r) |
Blue Tit (r) |
Cornubia (r) |
Hino Crimson (a) |
|
Johanna (a) |
Pioneer (r) |
PJM (r) |
Purple Splendor (a) |
R. Moupinense (r) |
Rose Greeley (a) |
Sherwood Red (a) |
White Dwarf (a) |
Midseason |
|
Bow Bells (r) |
Coral Bells (a) |
Dora Amateis (r) |
Elsie Lee (a) |
Everest (a) |
Hot Shot (a) |
Girard’s Gomer Waterer (r) |
Hahn’s Red (a) |
Helen Close (a) |
Holland (a) |
Hexe (a) |
Jean Marie de Montague (r) |
Louise Gable (a) |
Mimi (a) |
Moonstone (r) |
Nova Zembla (r) |
Purple Gem (r) |
Ramapo (r) |
Red Ruffles (a) |
Rocket (r) |
Rosaflora (a) |
Sherwood Orchid (a) |
Sherwood Red (a) |
Snow (a) |
Sunset Pink (a) |
Sweet Briar (a) |
Unique (r) |
|
Late |
|
Aladdin (r) |
Angelo (r) |
Autumn Gold (r) |
Cannon’s Double (a) |
Cunningham’s Blush (r) |
Evening Glow (r) |
Golden Lights (a) |
Gumpo Pink (a) |
Gumpo White (a) |
Ignatius Sargent (r) |
Irene Koster (a) |
Lee’s Dark Purple (r) |
Old Copper (r) |
Plum Beautiful (r) |
Polar Bear (r) |
Stewartsonian (a) |
Summer Snow (r) |
Summer Summit (r) |
Trilby (r) |
Tutti Frutti (a) |
Vulcan (r) |
White Catawba (r) |
Wilsoni (r) |
Windsor Lad (r) |
Witchery (r) |
|