JARS v55n2 - Rhododendrons in 3D: Dreams, Dwarfs and Delusions, Part II

Rhododendrons in 3D: Dreams, Dwarfs and Delusions, Part II
John Weagle
Halifax, Nova Scotia, Canada

Breeding in this area of the North Atlantic presents a unique problem - we start off with a rational plan and just when it has been determined that a plant is a winner, and a contestant to proceed to the next logical step, one wintry night's fury can end it all. Therefore, we often have to fly by the seat of our pants when pursuing new dwarfs. Ken Shannik and I have tried to introduce new rhododendron species and inter-specific and cutting-edge hybrids from other collectors and hybridizers into the rich bank of Nova Scotian material discussed in Part I of this article (JARS Vol. 55, No. 1, winter 2001). At the same time it is difficult to resist some entirely new routes. Progress has been slow but steady with the help of other keeners in the province. Primary (inter-specific) crosses have been the backbone of rhodo breeding programmes here. Uncomplicated hybrids like Gable's 'Moon Shot' ('Catalgla' x wardii ) and Rothschild's 'Prelude' ( wardii x fortunei ) have helped immeasurably to produce some fine large hybrids for coastal Nova Scotia, though the great skill of Captain Richard Steele is not to be under-estimated. The simplicity and straightforwardness of his winning crosses always amaze us. The work of the late Joe Brueckner excites us too because many of his crosses involve a thoroughly hardy species combined with previously unused species or hybrids. His plants have great potential for our area and the strategy for injecting them into local dwarf hybrids will be determined when his plants are fully assessed. Visionary breeders like Berg, Doi, Starling, Harvey, Peter and Kenneth Cox, Askjaer, Voitk and Lehmann (and the many other Danes and Swedes quietly working away) have had the great insight to make inter-specific hybrids. In doing so not only have they produced some brilliant new plants but they've given breeders everywhere the means to create smaller rhododendrons almost as varied as those in more favoured areas.

Lost in Action - smirnowii
In our milder coastal gardens, Rhododendron tsariense can be grown by committed rhodophiles. Like aureum , tsariense has thin flower texture and we're very keen to find a better clone. Twenty years ago Walter Ostrom and I put tsariense on yak ( R. degronianum ssp. yakushimanum ); he used yak 'Koichiro Wada' and I used yak 'Mist Maiden' - our results are identical. (If 'Mist Maiden' is a smir-yak, will someone kindly tell me why there is no apparent smirnowii influence in the F1 or F2?) These two handsome plants with improved flower texture are under 40cm (16 in) after fifteen years and sport marvellous indumentum. While appearing structurally weak with rubbery limbs, surprisingly they have never shown damage from snow or ice loads.

Year Round Beauty

Joe Harvey really got us thinking about the appearance of our rhododendrons year long. His thrust while living in Halifax was to produce elegant and interesting foliage coupled with good habit. (See his most interesting article "Forget the Flowers - Breed for Leaves" in JARS Vol. 39 No. 3, summer 1985). He contributed many seed lots to Atlantic Chapter's Seed Exchange in the 1980s and left some impressive new hybrids when he departed for Victoria, B.C. He is still actively pursuing these lines and is a regular ARS Seed Echange contributor. Joe crossed tsariense with smirnowii ; the little plants are cute but a bit too lusty. Still they could be an invaluable source of style and hardiness for the future. His crosses of ( adenogynum x tsariense ), ( insigne x tsariense ) and ( degronianum 'Enamoto'* x tsariense ) are good hardy gene pools and might produce some spectacular plants when crossed with our own (yak x tsariense ) F1, F2, Glendoick's ( tsariense x proteoides ) or the intriguing ( principis Vellereum Group x tsariense ) of Monica Johannsen, one of the "quiet" Danes, living in Jutland. Just talking about these hybrids makes the pulse rush and the mind too. Envision the super dwarf buns from an imagined mating of ( tsariense x proteoides ) x Barber's ( aureum x maximum ) F2 (see photo accompanying Part I). How tiny and tight can we go? Even smaller than Kentville's ( aureum x forrestii Repens Group) F2 or those choice minute selections of pseudochrysanthum ? Still in infancy, we have our own ('Haaga' x tsariense ) which could be used as a parent in the colder climes of northern Nova Scotia, Prince Edward Island and New Brunswick.

Rhododendrons in Steele's Bayport
Plant Farm
Good stud plants. Rows of ( R. brachycarpum x williamsianum ) F3 and
( R. brachycarpum x R. wardii ) F3 raised in a sunny field at
Steele's Bayport Plant Farm, near Lunenburg, Nova Scotia.
Photo by John Weagle

Dwarfs in Fur Coats

Now with such a wealth of material with which to work, what other avenues can be taken? Well, my own interests dovetails with Joe's - striking foliage and habit and if the flower is good so much the better. Our cool summers and soils have helped immeasurably with this pursuit and visitors from farther south are startled to see so many lepidote species and the Taliensias doing well here on the coast. We are lucky indeed that in the latter group proteoides and pronum , both extremely dwarf and delectable, thrive here in open breezy coastal gardens. These, la crème de la crème of all dwarf elepidotes, do not do well in the hot eastern United States and even here pronum can be a tad miffy, needing both sharp drainage and a watchful eye in drought until well established. Its hybrids seem much easier to please than the species itself, though Ostrom's 10-year-old pronum is a perfect specimen and sports a single fat bud as of October 2000 - a first for Nova Scotia. The following hybrids will surely be useful to future local breeders should they ever bud: ( proteoides x pronum WB93), several sibling ( pronum x proteoides ), ( clementinae x pronu m) (Cox) and (yak 'Koichiro Wada' x pronum ) Greer. All are painfully slow but completely impervious to wind and snowless cold. My fantasy cross of campanulatum ssp. aeruginosum x pronum would give us that blue-leafed dwarf we are missing, perhaps as stunning as the Royston form of caloxanthum ( campylocarpum ssp. caloxanthum ). Kenneth Cox has attempted this cross with no luck though I'm certain he will try again as the allure is irresistible.

One can hardly ignore the potential of proteoides after a visit to Warren Berg's garden. Warren's hybridizing efforts are indeed Olympian, and a visit to his plantation was an epiphany for me - a complete reassessment of my methods and goals was in order. When Warren sends a capsule of proteoides pollen one has a duty to use it wisely, somewhat akin to being passed an Olympic torch. And so I have crossed it with many species and grow every proteoides cross I can find in the ARS Seed Exchange knowing full well that Warren or Glendoick has probably done the same, years before. We have very small F1 crosses of proteoides with alutaceum var. russotinctum , recurvoides Hydon, taliense , roxieanum **, pseudochrysanthum , phaeochrysum 'Green-mantel' R.11325, dignabile and chamaethomsonii . To date all are very dwarf, perky and attractive. Our tiniest is ( wardii KW4109 x proteoides ), followed closely by ( forrestii Repens Group x proteoides ). The latter is just planted, and we envision a creeping indumented stunner with waxen red bells; you have to be a bit of a dreamer in this business!

In their recent article (JARS Vol. 53, No. 4, fall 1999), Shirley and Allan Anderson proposed crossing maximum with proteoides . We did this in 1995 with a good pink form of maximum . The same year we crossed proteoides with creeping brachycarpum . The maximum cross gave very glossy leaves. Both crosses should make excellent super-hardy parents for future use, should our other crosses backfire. Now, if you are thinking that we were terribly clever to do such a novel cross, consider this: Harry Wise of Charleston, West Virginia, contributed hand pollinated seed of maximum x proteoides R.147 (ARS 85-1182), ten years before! All too often we are day-dreaming and not paying attention.

Our experience with proteoides hybrids indicates that the faster they get out into fresh air and cool soil the higher the survival rate. Warm roots in pots are utter anathema to them. Once planted, their rugged constitution is astounding; the more wind, the better they look. Rhododendron aureum and Repens Group, proteoides and pronum , camtschaticum and redowskianum , lapponicum and the extremely dwarf yaks, ludlowii and lowndesii are as finicky. Are the traits we seek - shortened growth, hyper-twigginess and creeping or dwarfed habits - peculiar to site-specific species? If such sites are sunny but cool and windy, with the short growing seasons of high altitudes or northerly latitudes, then we may be well situated. Aside from the compact catawbiense on the southern balds, do the dwarfs of our favourite genus exist in warm areas? Or, by retreating to the shade to avoid incineration, has nature precluded warm-blooded Lilliputians? Breeders in such areas should get proteoides and pronum pollen on heat-tolerant species like hyperythrum and anwheiense . Your dreams of dwarfs may be realized with a little imagination.

And proteoides and pronum are but two species in the magnificent subsection Taliensia. This group has some of the best foliage in the genus, good cold hardiness, a wonderful colour range and is an untapped goldmine waiting to be discovered by the hybridizers of the new millennium.

A promising new dwarf yellow rhododendron
{[('Bellefontaine' x 'Goldsworth Yellow') x degronianum ] x ( aureum x 'Prelude') BPT#80-5}.
A Craig hybrid which combines his own Kentville Research Station hybrid with
Cpt. R.M. Steele's early yellow. A promising new dwarf yellow.
Photo by John Weagle

Yellow and Orange

It seems that the quest for hardy yellows has consumed the last twenty-five years of the 20th century in eastern North America. Rhododendron aureum figures prominently in many local yellow hybrids as it reliably transmits yellow and will dwarf almost anything. Steele's early bright yellow BPT#80-5 ( aureum x 'Prelude') is a fine dwarf and one of the yellowest. It reaches only 1 meter (3 ft) in thirty years. A good performer here on the coast, it, like aureum itself, is unsuited to most of the warm eastern United States and areas where the growing season is too long, winters are too mild and early spring warmth is followed by devastating late frosts. Foliage and buds can both get badly nipped in those scenarios. Don Craig's {[('Bellefontaine' x 'Goldsworth's Yellow') x degronianum] x [aureum x 'Prelude] BPT#80-5} (see photo) proves that BPT#80-5 has breeding potential. (Steele has selfed and sibbed BPT#82-1, on 'Hong Kong'. His plants look promising as do those grown by Bill Wilgenhof.) We have crossed BPT#80-5 with proteoides in the hope of an even smaller yellow. Though untested, 'Berg's Yellow'* would almost certainly fail here as 'Mrs. Betty Robertson' has not been "de-tenderized." ARS 96-462 ('Berg's Yellow' x proteoides ) F2's toughness in my garden indicates that hardy yellow dwarfs are quite possible using proteoides . With this in mind, we have combined Warren's ('Berg's Yellow' x proteoides ) F1 with BPT#80-5. That should shake up the genes a bit, with aureum and proteoides in the same hybrid. But, are we breeding for miffiness? We may work the late Basil Potter's cross 'Serendipity' ( aureum x yak), my own 'Crest' x aureum , Ostrom's [( brachycarpum x aureum ) x caloxanthum ] (see photo), Steele's brachycarpum x wardii F3's (see photo) or his tightest (yak x Moonstone Group) into the progeny some day. When greater hardiness is attained we will put them on Steele's ( aureum x 'Binfield') or maybe even Bill Moyles' tantalizing 'Baby Grand'* ( aureum x sinogrande ).

[(R. brachycarpum x aureum) x R. caloxanthum]
A new Ostrom hybrid, [( R. brachycarpum x aureum ) x R. caloxanthum ], shown
growing seaside near Peggy’s Cove, Nova Scotia. A taste of things to come from Nova Scotia.
Photo by John Weagle

A recent landmark was a take of proteoides on Cpt. Steele's super orange hybrid ( vernicosum 'Mount Siga' x 'Queen Elizabeth II') BPT#95QER. Orange may be too much to hope for in the F1 but increased flower substance and size may not. In a recent e-mailed time bomb Shirley Anderson casually mentions having pollen of ( dichroanthum x proteoides ). Visions of orange and the mind starts racing: why not put this on my ( aureum x [yak x Fabia Group]) or on Barry Starling's striking hybrid 'Easter Chick' ( aureum x dichroanthum ssp. scyphocalyx ) or in the future, on ([ vernicosu m 'Mount Siga' x 'Queen Elizabeth II'] x proteoides ). And what about Doi's ([ dichroanthum ssp. apodectum x brachycarpum Roseum Group] x aureum )? He has just pollinated it with Ostrom's ([ brachycarpum x aureum ] x caloxanthum ) and may have scored a direct hit on orange. Recent conversations with Carl Lehmann indicate his creations involving citriniflorum var. horaeum (see JARS Vol. 49, No. 2, summer 2000) might be suitable bedfellows for some of the Nova Scotian attempts at this colour. The possibilities are limitless, the quest for orange most alluring and delusions persistent.


Another goal has been to get the flower substance of Rhododendron fortunei into a proteoides cross as both proteoides and pronum have rather thin flower texture. All attempts have failed every year, including a much-needed one with a hardy Steele decorum . I fear proteoides could be incompatible with the subsection Fortunea, though I hope someone will prove me wrong. We are required, therefore, to proceed through the back door, and my two recent proteoides takes are of great importance to us. The first on a hybrid known locally as 'Barbara Hall'* (which is a Steele hybrid ['Road Red'*** x 'Prelude'], 25 percent fortunei and close to the Dexter 'Parker's Pink' but hardier) and on 'Betty Hume', a Dexter pink fortunei hybrid with rubber-like flower texture. Perhaps we will at last get flower substance and a stronger colour. Another route would be to cross Steele's pink "forcats" with proteoides ; ( fortunei x 'Catalgla') is a cross made in heaven and so happy in the Bayport woodland that thousands of self-sown seedlings carpet the floor beneath the now-towering 5+ meter (14 ft) high row of plants. A sturdy ladder will be required!

Just for Kicks

Some bizarre crosses attract us as well. Rhododendron ([( bureavii x 'Ken Janeck') x 'Sir Charles Lemon'] x proteoides ) from the ARS Seed Exchange grows slower than a stalagmite, but the prospect of stunning foliage makes it well worth the wait. One wonders what ([yak x longesquamatum ] x proteoides R.151) ARS 96-#1384 and (['America' x 'Carmen'] x [ aureum x 'Prelude'] BPT#82-1) will bring. With hand lens we admire the youngsters, while the men in white coats stand ready. Cross our ( forrestii Repens Group x proteoides ) with Kentville's ( aureum x forrestii Repens Group) F2 and we may be locked up!


Hybridizers in very cold climates might well consider using Dave Hinton's ([ brachycarpum (as ssp. tigerstedtii ) x ( smirnowii x yak)] x proteoides Berg). The seed parent 'Sandra Hinton' is an extremely hardy plant bred by Dave and has tolerated temperatures near -35°C (-31°F) at his Orono, Ontario, garden. A number of recipients of this ARS seed lot have suggested that the cross did not take. I noted upon sprouting that while many seedlings showed no proteoides influence, a fair number did show its unmistakable characteristics. We await their progress and shall distribute some to colder climes for testing and hybridising. Dwarfs could be marching much farther north!

In Hokkaido, Dr. Yasayuki Doi has done much that is of great interest to us. He has combined brachycarpum Roseum Group (see the Cox & Cox Encyclopedia of Rhododendron Species, page 138), a very dwarf and wind-tolerant strain, with the finest species and emphatically coloured hybrids. The successful colour inheritance using this brachycarpum will astound the most jaded hybridizer and surely shatter some traditional inheritance notions! His work, of which this is but one facet, merits a lengthy article in the Journal. We are growing quite a few of his many gems and in time will incorporate more of them into our own dwarf material to increase both hardiness, colour, diversity and adaptability.

Dwarf Headaches

Breeding for a good red—dwarf, medium or tall—is "la cause célèbre" here in the cold north. The late Joe Brueckner once told me "getting good reds will be very difficult, the yellows will come easily." There being no truly hardy red species makes it very difficult to formulate a breeding plan for red, especially dwarf reds. The brilliant red creeping species Rhododendron forrestii Repens Group 'Tower Court'* has persisted here, though it is cranky customer to grow. But how can we use it to produce a super-hardy clear barbatum red? Kentville Research Station's extremely dwarf ( aureum x Repens Group) F2, an old Hobbie cross, bordering on rose red, might be useful, albeit a perilously early bloomer even here. The Doi and Jens Birck plants of ('Fantastica' x proteoides ), our own ('Morgenrot' x proteoides ) and [('Lath House Red'**** x yak) x proteoides ] perhaps point the way for us. Someday we will cross them with Repens Group and the super hardy Finnish 'Elviira' ( brachycarpum (as ssp. tigerstedtii ) x forrestii Repens Group). We cannot thank the Finns enough for that ground-breaking red hybrid. My own backcross of 'Elviira' x forrestii Repens Group 'Tower Court'* should bud and bloom red in 2001, and we hope for a hardy Repens look-alike. Ken Shannik has already crossed many red, yellow and orange species and hybrids with 'Elviira'. Blooms are anxiously awaited, especially on his ('Elviira' x barbatum ), ('Elviira' x 'Elizabeth'), ('Elviira' x 'Baden-Baden'), ('Elviira' x 'Lionel's Red Shield'), ('Elviira' x Steele's (yak x [Repens Group x 'Barclayi' Group]) and ('Elviira' x Doi's ['Carmen' x brachycarpum Roseum Group]). We presume that 'Elviira', which is reputed to tolerate -29°C (-19°F) or lower, can toughen its mates. From these, with luck, will come some dwarf, emphatically red-flowered plants. Factor Steele's red ( aureum x lanigerum 'Round Wood') into the final equation and we could be on the road to Nirvana. As a safeguard, I have crossed ('Haaga' x forrestii Repens Group) and ('Francesca' x forrestii Repens Group 'Tower Court'*) should other Repens combinations fail due to tenderness. 'Henry's Red', not a plant we hold in high regard, was the only red hybrid to accept Berg Pollen of ( sperabile x proteoides ); the plants look very unusual and will be closely watched. Barry Starling has been a great help to us, growing our crosses and sending seed from his own. He tells us that his now-budded [ aureum x ( forrestii Repens Group x 'Popacatapetl')] are as compact and prostrate as Repens itself. Bravo to aureum and Repens for flattening effects! This hybrid and his ('Elviira' x [ forrestii Repens Group x 'Popacatapetl']) will undoubtedly prove slightly tender here but their pollen might be very useful. One very slow (yak x 'Carmen') from the ARS Seed Exchange is at last budded here and ready for pollen. My own ('Sumatra' ['America' x 'Gertude Schäle'] x 'Lionel's Red Shield' ['America' x 'Carmen']) is as yet un-budded but should someday be worked into the Craig 'Elizabeth' hybrids and Brueckner sanguineum hybrids. Yasayuki Doi's ('Carmen' x brachycarpum Roseum Group) (see photo) inspires us; it will be of great use to breeders in Atlantic Canada in the quest for a truly hardy red.

('Carmen' x R. brachycarpum Roseum Group) #2
Dr. Yasuyuki Doi’s ('Carmen' x R. brachycarpum Roseum Group) #2 will be
of great use to breeders in Atlantic Canada in the quest for a truly hardy red.
Photo by Yasayuki Doi

Reality Check

Our recent seedlings have not been easy to grow in the early stages. Hardly surprising, given that some of the species involved are not without cultural challenges. It will be interesting to see if these shortcomings are passed on to their hybrids. For instance Rhododendron aureum , very temperamental in youth but rock-hardy, sports a very distressed look in winter with yellowing, drooping leaves and appearing for all intents and purposes to be in the final stages of phytophthora. As well, blooming during the earliest days of spring, its flowers' texture lack sufficient substance to take the battering of rain and wind; an ivory seedling we grew from the Arnold Arboretum's Hokkaido Expedition is a rare exception. Once established, the Steele aureum hybrids are, for the most part, quite presentable in winter. Rhododendron brachycarpum (as ssp. tigerstedtii ) has this same distressed and yellowish winter guise especially severe in full sun. Its leaves are the first to hang straight down - and I mean straight down! - with a good freeze, and they don't fully recuperate until frost has completely left the ground. The very dwarf Roseum Group of brachycarpum we hope will be an exception, but we have not had it long enough to be certain. Reds are generally miffy but forrestii Repens Group has a litany of drawbacks; it is intolerant of heat, warm soil, nitrogen fertilizer, overhead competition and planting near sun-drenched foundations or under roof overhangs. As if that weren't enough, it also detests poor drainage, drying out and is a shy budder - a fault luckily not passed on to most of its progeny. Peter Cox's report on a trip to Yunnan in the spring 1995 Journal says much about this species and its wants; the time was late May: "Sadly this part of the meadow covered with R. forrestii was still under snow"! Surely, by the time it finally emerged to both grow and bloom, frost was no longer a threat. Yes, we are quite mad to use it, but do recall Kingdon Ward's likening of the wild Repens to sheets of molten lava when in bloom - who can resist? Rhododendron maximum , according to the Americans, is intolerant of too much exposure to sun and wind and requires a relatively moist spot. Here it will happily grow in full sun in driveway gravel when fully established.

Our work in Nova Scotia may well be of local importance only, as both heat and late frosts seem to plague the big eastern U.S. market areas. And, will our dwarfs suddenly become rank growers in benign climates with longer growing seasons? Time will tell. We would be quite content to produce just a few good-lookers and a respectable bank of sturdy genes for our younger breeders to use. Without the support and generosity of our local comrades and an abundance of inspiration and superb pollen from the cognoscenti: June Sinclair, Warren Berg, Yasuyuki Doi and Peter and Ken Cox, we would be still at the starting gate. I will report back when our new hybrids start blooming, but don't hold your breath. I note in the inventory that I did the maximum x proteoides cross in 1995 and the plants are still under 7.5cm. (3 in) - in fact I still have some seedlings in the original seed pot!

The Cure

The need to recruit younger members - the breeders of the future - becomes especially urgent as we breed for dwarfs and slow-growing rhododendrons. Much of the work discussed will have to be done by them. I urge you to write about your experiences and ideas. Offer your pollen and plants for breeding purposes and share your enthusiasm and dreams (delusions too) with anyone that shows an interest.

* Name is not registered.
** The Cox team tells us that roxieanum var. parvum and proteoides aff. (Hillier's clone) are in fact Mother Nature's jump on us all - proteoides x roxieanum ; it would be interesting to repeat this cross using the various leaf forms of roxieanum .
*** 'Road Red' is Steele's unregistered name for an old unknown red ironclad growing roadside in Digby County, N.S. It was planted in the late 1800's.
**** ('Lath House Red x yak), another unregistered Steele hybrid with fine indumented foliage and perfectly round small pink trusses. Hardiness superior.