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Q-R

Species Rhododendron Descriptions By Name
qiaojiaense
R. qiaojiaense

First a Mandarin lesson: the rhody’s name is chow-ja-en-se. Next, the plant is a winner. The almost orbicular leaves have a thick texture, and the plant seems to branch readily, making what should be a compact rounded garden beauty. In the subsection Fortunea, it is most likely closely related to R. decorum, so it belongs to a distinguished branch of fine rhododendrons. The new growth often has the bronze color shown in our photograph. R. qiaojiaense seems to be easy to grow.

Only recently introduced from Yunnan, China, it is too soon to know how tall it will grow in our NW climate. In its native habitat it grows between six to twelve feet tall, probably less here. It's best grown in a mix of sun and relief from hot afternoon blazes. Try small amounts of fertilizer on Valentine’s Day and Mother’s Day. Good drainage always helps.

R. quinquefolium

Here’s another of the superb Japanese deciduous azaleas – many would say the best.  In early spring its apple green leaves emerge in whorls of four or five rimmed in shades of red!  The dainty white flowers appear with the leaves, and the plant seems to layer itself as the new shoots emerge from within the terminal buds.  In autumn, the leaves turn shades of yellow and red; winter reveals the intriguing branch structure of this much sought-after rarity.

R. quinquefolium  makes a wonderful container plant that always draws attention.  In the ground, it may reach four feet in ten years.  Pick your spot carefully as it does not like being transplanted once established.  It doesn’t mind some heat, but it does like some shading from the sun, especially the afternoon sun. Its tender leaves are easily scorched.

quinquefolium
R. racemosum

Here’s a dainty shrub that is quite common in many parts of western China. It flowers readily even on young plants with blossoms that range from pure white to quite deep pinks in March and early April. It ranges in height from a small mound to more upright forms that respond well to pruning when young. This plant is grown from seed collected in the mountains of China and has its own distinctive characteristics.

R. racemosum most likely has some drought resistance as it is often found in extremely dry spots in China. Give it some sun but don’t bake it. Keep it pruned the way you want it.

racemosum
R. rex ssp. fictolacteum

This relative of R. rex can claim regal status as well. Leaves of polished dark green can grow up to 12 inches, with a thick tawny orange indumentum (that fuzzy stuff on the underside of the leaf).  This is a reliable plant with real class whose large white flowers always come with a blotch, flare or prominent spots.  You can expect an five to six foot shrub in about 10 years.

R. rex ssp. fictolacteum's leaves often curl in direct sun or in periods of cold. They return to a flatter shape when things are more normal (at least for fictolacteum). It's hardy to 0° Fahrenheit.

rex ssp. fictolacteum
R. rex ssp. rex

This is indeed the king of shrubs!  Its glossy, leathery leaves are a commanding size and deserve respect.  The tawny indumentum on the underside of the leaf adds interest, but the crowning glory is the truss of up to thirty white flowers flushed with rosy tints.  Truly regal!

 

R. rex can be tree-like in a woodland setting or a shrub in a more open space. It may grow to 5 feet in ten years. It will enjoy morning sun or even dappled sun all day, but protect it from periods of intense sun. It is hardy to 0° F.

This is one of the great species of western China – by growing it here, you may help to preserve this important gene pool which is threatened in its native habitat.

rex rex
R. rothschildii

This rhododendron most likely originated as a hybrid of R. arizelum and R. praestans in the wild and now has formed a stable population in Yunnan. It’s a handsome “big leaf” whose leaves taper down to a flat petiole. The indumentum is brown and granular. With glossy leaves, it’s a stunning plant.

R. rothschildii’s flowers vary in color from creamy-white to pale yellow to pale pink. It will reach five feet in ten years. Hardy to perhaps 5° F.  To quote Peter Cox, “Rare.”

rothschildii
R. roxieanum var. oreonastes

This variety of R. roxieanum includes the narrowest leaved-forms and is well worth growing for its foliage alone.  The interesting, thin and sharply pointed leaves give it an exotic look and feel. 

 

It will become a mounded shrub, perhaps 4 to 5 feet high.  Native to China, but raised here in Western Washington, it’s hardy, well-behaved, and relatively slow-growing.  Flowers are white with purple spots.

R. roxieanum will like some sun in a bright location and needs good drainage. It is hardy to -10° Fahrenheit.

roxie oreonastes
R. roxieanum var. roxieanum

R. roxieanum is best known as the var. oreonastes – the narrow leafed form, but R. roxieanum comes in a variety of forms, including this one with wider leaves and a much shorter height.

It will become a mounded shrub, perhaps 3 feet high.  Grown from seed collected from moms who were only that high, these plants have polished green leaves that are clothed with a rich cinnamon indumentum. The current year’s leaves start out with a pure white indumentum which slowly turns that cinnamon-brown during the course of the season. Flowers are white with purple spots.

Give it some sun and that perfect drainage.

roxieanum var. roxieanum
rubinginosum
R. rubiginosum

R. rubiginosum is a widely distributed rhododendron in parts of Sichuan, Yunnan, Tibet and Myanmar and therefore shows a great deal of variation in flower color.  In the wild, it can become quite large but is amenable to pruning in our gardens and can make a fine screening plant. It enjoys a fair amount of sun and rewards by covering itself with flowers in shades of pink to purple. The flowers usually come with a blotch or spotting. It has leaves that are densely scaly on the underside. In our gardens it will probably reach 6 feet in ten years if left unpruned. It is hardy to approximately 0° F.

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