Rhododendrons

My "grandfather," Reuben Hatch

Today's Rhododendron blog is overdue, I feel, and its subject is a topic I must get behind me, especially since I'm not a "Rhododendron guy." But you wouldn't know that from visiting our gardens, which are chock-a-block with choice species and hybrids. This situation is largely due to a long-time friendship with one Mr. Reuben Hatch, known affectionately as my "grandfather," for he used to operate a one-man Rhododendron nursery, and provided plants for the "discerning gardener." Over the years he foisted many plants on me, taking my maples in return, so that today these special Rhododendrons provide a rather "snob" element to the Flora Wonder Arboretum.

The genus Rhododendron consists of over 1,000 species, and the "lumpers" and "splitters" are endlessly fighting over their classification. The name Rhododendron is derived from ancient Greek rhodon, meaning "rose," and dendron meaning "tree." I have seen many of the species in the wild, all the way from America's Pacific Northwest to the fifteen-thousand-foot elevations in the Himalayan mountains. But one doesn't need to travel so far to see world-class collections. Portland, Oregon can boast of the Crystal Springs Rhododendron Garden, where the plants can be appreciated year-'round, even when they're not in bloom. Further north, in Washington state, is the Rhododendron Species Garden, a foundation that features one of the most comprehensive collections in the world. These gardens are somewhat over my head, but there are a number of species, such as orbiculare, roxieanum, thomsonii and others that I can identify on sight.

Rhododendron orbiculare 'Edinburgh'

Rhododendron orbiculare 'Edinburgh'

Rhododendron orbiculare 'Exbury'

Rhododendron orbiculare 'Exbury'

Acer griseum

Davidia involucrata

Cornus kousa var. chinensis

So let's begin with these species, with orbiculare first. It is native to Szechuan, China, and features rounded heart-shaped leaves that are horizontally (elegantly) held, green in color above and glaucous beneath. Flowers are pink before fully opening, then become a more whitish pink when fully opened. Remember that a species can vary in appearance in the wild, so not only should you covet an excellent species, but also a particularly lovely form. I have two such forms, which I identify as Edinburgh and Exbury, coming from two of the most famous gardens in the world. We have E.H. Wilson to thank for the introduction of orbiculare (in 1904), the same plantsman who introduced Acer griseum (in 1901), Davidia involucrata (in 1904), Cornus kousa var. chinensis (in 1907) and a whole lot more.

Rhododendron roxieanum var. oreonastes

Rhododendron roxieanum var. oreonastes

Rhododendron x 'Blewbury'

Rhododendron x 'Blewbury'

Rhododendron roxieanum, also from China, can vary in nature, especially with the shape of the leaves, which could partly be due to hybridization. We grow the variety oreonastes, which features long narrow lobes, mainly because I'm a fan of the skinny, in all things. The flowers are white, but not very attractive to me, and I would prefer that it never flowered at all. Plant-hunter George Forrest coined the roxieanum name, memorializing a Mrs. Roxie Hanna who lived as a missionary in Tali-fu, China, now known as Dali, an interesting town in Yunnan province where I have also hunted for plants. The oreonastes word refers to "compressed mountain dweller," and my twenty-year-old plants are only four feet tall by five feet wide. We also grow 'Blewbury', a cute English hybrid with the seed parent roxieanum var. roxieanum, and the pollen plant being Rhododendron anwheiense, the latter a plant I have never seen.

Rhododendron thomsonii

Rhododendron thomsonii

Rhododendron thomsonii was introduced from Sikkim by Sir Joseph Hooker in 1849, and named in honor of William Thompson, an Irish naturalist. The Rhododendron species is spelled without a "p," even though Thompson's name includes one, but I don't know why that happened. Anyway, I saw thomsonii myself in Sikkim, or at least a close species that I took for thomsonii. They were tree-like, and in some cases so thick that I walked beneath them, admiring the richly-colored exfoliating trunks. Flowers are bell-shaped and deep blood-red, and the round leaves are an attractive blue-green, especially noticeable on young plants. Thomsonii is a parent to many hybrids, but I don't see how you could improve upon the species itself.

Rhododendron strigillosum

Rhododendron x 'Taurus'

Rhododendron x 'Taurus'

Strigillosum is a wonderful species from Szechuan, China, and one that I can easily identify due to bristly young stems. The species name was in use in Roman times, as a "strigil" knife, an instrument that was used in the baths to scrape off dirt and sweat from plebian bodies. In any case, the Rhododendron features brilliant crimson flowers which are beginning to open now. The hybrid x 'Taurus' is a superb result between 'Jean Marie de Montague' and strigillosum, and was bred by the late Dr. Mossman, a noted plantsman from Vancouver, Washington, one who was an important and generous friend for me at the beginning of my career. 'Taurus' will eventually reach ten feet tall and wide, and possibly larger when one is finally one hundred years old, so site appropriately.

Rhododendron x 'Daphnoides'

Rhododendron x 'Daphnoides'

I have an impressive specimen of Rhododendron 'Daphnoides', an eight-foot round ball with small, Daphne-like leaves. It has outgrown its place in the Display Garden, but rather than move it, Phil will "tree it up," which means to limb-up and reduce the canopy; then it won't look like such an enormous blob which is currently blocking the view of other plants. I find it interesting that argument still exists over 'Daphnoides', whether it is a hybrid or merely an unusual form of Rhododendron ponticum. It was developed by T. Methven and Sons in England in 1868, and I can imagine there are enormous specimens in Britain.

Rhododendron campanulatum ssp. aeruginosum

Rhododendron campanulatum ssp. aeruginosum

Rhododendron campanulatum is a common species throughout the Himalaya, but the subspecies or variety aeruginosum (which I always have to focus carefully to spell korrect) is certainly one of my favorite of any flowering plant. It's appeal is not due to its blossoms, but rather the metallic blue-green of the new growth. Older leaves, like now in winter, are more green than blue, but in spring they are strongly blue, and cause gasps of wonderment when plant lovers encounter it for the first time. It comes from alpine regions from 12,000' to 14,500' in altitude. I have never seen it in the wild, but I imagine the sight would be spectacular. Go ahead and check out the leaves' undersides, which are fuzzy with indumentum, and are cinnamon-colored. Before you are tempted to add aeruginosum to your salad, know that the leaves contain a poison called grayanotoxin which can cause liver damage. By the way, aeruginosa is Latin meaning verdigris or "copper rust," and a Pseudomonas aeruginosa can be fatal to animals and humans, causing infections in hospitals. I've grown the Rhododendron for ten years, but it's funny that I can't even recall the flower color.

Rhododendron augustinii 'Smoke'

Rhododendron augustinii 'Smoke'

Rhododendron augustinii is a small-leaved Chinese shrub, and its name honors Augustine Henry who first found it in China in 1886. In the wild flowers vary from white to violet-blue. The cultivar we grow is 'Smoke', which is notable for its luminescence on cloudy days. I don't really care for the plant when it's out of bloom, unlike other aforementioned species.

Rhododendron bureavii

Rhododendron bureavii

Rhododendron bureavii

Rhododendron bureavii is another species I like and can identify on sight, and you can see from the photo above that it has nothing to do with the boring flowers. It is a slow-growing compact species with interesting brown to rusty-red new growth. It will burn in full sun in Oregon unfortunately, which I had to learn the hard way, but when sited with afternoon shade in moist but well-drained soil, it becomes one of a Rhododendron collector's favorite species. It was also introduced by E.H. Wilson in China in 1904, and its name honors a French professor, E. Bureau, who lived from 1830 to 1918, but I don't know why he was so honored.

Rhododendron clementinae

George Forrest with his dog, N_ _ _ _r

I don't know very much about Rhododendron clementinae, except that it was named for the great plant collector George Forrest's wife. Of all the famous plant explorers and collectors throughout history, the Scotsman George Forrest is probably my favorite of all, my "hero of horticulture." I won't fully explain why at this time, but I encourage readers of my blog to read George Forrest Journeys & Plant Introductions, a RHS publication. You'll discover that Forrest was a "real" man, in both brain and brawn, with a tireless work ethic and superb organizational skills. I can only imagine how successful Buchholz Nursery would have become if somebody like Forrest was running it.

Rhododendron keiskei 'Yaku Fairy'

Rhododendron keiskei 'Yaku Fairy'

Rhododendron keiskei 'Yaku Fairy'

Rhododendron keiskei is a dwarf low-growing species from Japan, and a favorite with rock-garden aficionados.  I was given a fantastic old specimen by "my grandfather," Reuben Hatch, one of the most large in cultivation of the cultivar 'Yaku Fairy', for it was found on the botanically-rich Yakushima Island, at the very south of Japan's last major island, Kyushu. My 'Yaku Fairy' is only 10" tall by 45" wide in 45 plus years, and is a floral treasure that probably should be elsewhere, like in the Japanese Emperor's garden. The species keiskei honors the botanist Keisuke Ito, who lived from 1803-1901, who ended his life with long white hair and beard, and whose photo I have seen. Of further interest is that Ito was one of Phillip von Siebold's students, when that great plant collector was stationed in Japan. You can revisit the blog of December 28, 2012, Species of Maples Named for People, Part 2, to learn more about von Siebold.

Sadly I must report that Yakushima Island, which really is an intense Mecca of floral species, features trees (Cryptomeria japonica) that are over 3,000 years old, but is in great danger. Pollution from China is killing the Chinese, but it is also spreading world-wide, and particularly affects the ecosystem of Yakushima, a problem overlooked by the zealous capitalists of the aggressive Chinese economy. Yes, we live in a shitty world.

Rhododendron macrosepalum 'Linearifolium' in spring

Rhododendron macrosepalum 'Linearifolium' in winter

I mentioned before that I'm partial to the skinny, so of course I love Rhododendron macrosepalum 'Linearifolium', and too bad that it couldn't have been given a more catchy name. It has long been cultivated in Japan, but is apparently unknown in the wild. Narrow green leaves can turn to orange in winter, and it is only semi-evergreen at Buchholz Nursery. It is a tender plant for Oregon, and I have lost it before outdoors, but a nice specimen resides in our "fun-house," Greenhouse 20, that I frequently mention. Another interesting characteristic is that 'Linearifolium' can have blooms throughout the year, and above is a photo from February.

Rhododendron occidentale

Rhododendron occidentale

Rhododendron macrosepalum is considered  an "Azalea," and so too is Rhododendron occidentale, which is a medium-size deciduous shrub. It is native to southern Oregon and California, and when grouped in mass in the wild, the floral odor can overpower you on a sunny spring day. It was first cultivated in England, with seed being sent to the Veitch Nursery in 1850 by the employee-collector William Lobb. Dr. Mossman, mentioned previously as the hybridizer of Rhododendron x 'Taurus', was instrumental in selecting special forms of the diverse species, and many are now conserved in the Smith-Mossman "Western Azalea Collection" at Lake Wilderness Arboretum in Washington state.

June Sinclair with Rhododendron sinogrande

Rhododendron sinogrande

Rhododendron sinogrande

Rhododendron sinogrande is an impressive species with huge glossy-green leaves. Flowers are creamy-white with a red blotch, but pale in comparison with the enormous leaves which are considered the largest of all Rhododendrons. Unfortunately it is only hardy to 10 degrees F, USDA zone 8, and I keep my single tree indoors. Sinogrande was discovered by George Forrest in 1921, growing at 11,000' in western Yunnan, China, but it has also been discovered in Burma and northern India.

Rhododendron x 'Coastal Spice'

Unfortunately, a wonderful hybrid, 'Coastal Spice', is also a zone 8 plant, and I keep it near the sinogrande indoors. It was bred by the late Jim Gerdeman, who grew it on Oregon's central coast, where he resided in a banana-belt environment. 'Coastal Spice' is powerfully odiferous, and I think it has Rhododendron edgeworthia blood in it. I envied Gerdeman's benign climate, as he developed a great five-acre garden with a very choice collection of trees and shrubs. The only problem was the kook who lived next door, a woman convinced that exotics grown at the expense of native brush was certain to ruin the environment. She would sneak into the garden and remove plant labels, just to pester nice-guy Jim.

Rhododendron x 'Winsome'

Far more hardy is an old Bodnant hybrid, 'Winsome', with parents of giersonianum x 'Humming Bird'. Pendant flowers are an unusual pinkish-orange, and our twelve-year-old tree is totally covered in blooms in April. Bodnant is a 130-acre English garden that now belongs to the National Trust, and was voted by Daily Telegraph readers in 2000 as their favorite (or favourite, as the English say) garden in England.

Rhododendron x 'Seta'

The final Rhododendron I'll discuss is 'Seta', which is another Bodnant hybrid (moupinense x spinuliferum), which is blooming for us today. It was produced in 1933, but is still popular today for its delicate appearance and vivid pink blossoms.

There, you've made a little trip through our gardens, but appreciate all the hard work the plant collectors and hybridizers accomplished to bring us choice garden plants. While I'm not a "Rhododendron guy," I can understand the enthusiasm shared by those who are, for they really are handsome and useful plants, and most of them come with an interesting story as well. If I was allowed to make just one proclamation, it would be to prohibit the use of the words Rodies, Rhodys and the like, and always call the damn things by their proper name, Rhododendrons!