JARS v41n4 - Why Grow Species?

Why Grow Species?
Felice Blake
Kallista, Victoria, Australia
Reprinted from the Victoria Chapter Newsletter

It would seem to be an almost undisputed fact that the great majority of new gardeners venturing into the world of rhododendrons choose hybrids with big, gorgeously flamboyant trusses to fill their gardens with instant spring colour. Perhaps, on reflection, the new gardener might pause to wonder why most of his newly acquired beauties are not so remarkable for the rest of the year. His curiosity might be aroused, and hopefully he will delve further into the rhododendron world, then sooner or later he will discover the subtle delight of the species.

The acquisition of one's first species can open the door to an enticing new world. My first species was acquired about 25 years ago. It was R. griersonianum with its outstanding geranium red flowers, so different in both flower and leaf, to the usual hybrids I had been growing. I really felt I was venturing into unknown but tantalizing territory. We were then living in suburban Melbourne with the usual small suburban garden, but we would quite often drive up to the Dandenong Ranges, about 20 miles away, and explore the nurseries. It is a true but sad fact that in those days the nurseries carried a much wider range of species than they do now, and so R. griersonianum was soon followed by R. williamsianum , nuttallii and schlippenbachii . Such was the very modest beginning to the search which still continues today, our interest in species has never flagged over the years.

Not many years later we made the big move from suburbia to the Dandenongs, taking our few species (plus a host of hybrids) with us. We soon found that this was rhododendron country par excellence . Deep friable chocolate volcanic soil was ours, rainfall of about 50" - 60" each year, winter with little snow or frost, summer may be a little hot at times, but tolerable for most rhododendrons as giant eucalypts gave protection from excessive sunshine. We had the right conditions for exploring the rhododendron world.

We soon found that species rhododendrons are a remarkable breed of plants, amazingly tolerant of a wide variety of climatic and growing conditions. This is most remarkable when one considers that species growing in the wild on the "eaves of the world" in the high Himalayas, in the mountains of Tibet and China and Siberia and many other far away places, can thrive happily in all sorts of conditions in America, Europe, New Zealand and Australia.

It was not long before species began to dominate our rhododendron lives. We found we could grow, and flower in due course, some of the big-leafed beauties of the Falconera and Grandia subsections, including R. grande , sinogrande , macabeanum , rex , fictolacteum (now considered to be a subspecies of R. rex ), magnificum , giganteum , montroseanum (known then as R. mollyanum ), arizelum , sidereum , hodgsonii , falconeri and eximium (now a subspecies of R. falconeri ). These thrived wonderfully beneath the giant eucalypts.

Eventually most of them delighted us with their almost incredibly magnificent flower trusses, but just as fascinating as the flowers is the incredible beauty of the new foliage unfurling. As with so many species rhododendrons the foliage of these big ones provides so much year round interest that the flowering almost becomes a secondary consideration.

Key to: "Some leaves from the garden"
Beginning at top centre - R. falconeri , R. magnificum , R. rex ssp. rex , R. elegantulum , R. haematodes ssp. haematodes , R. pachysanthum , R. anthopogon ssp. anthopogon , R. niveum , R. roxieanum var. roxieanum , R. balfourianum , R. tsariense , R. bureavii , R. arboreum ssp. cinnamomeum var. cinnamomeum , R. falconeri ssp. eximium .
In centre - R. arboreum (from seed collected in Nepal).

Although we had to leave the largest plants behind when we moved to our present smaller garden at a slightly lower level in the ranges, we still are able to grow quite an interesting variety. R. falconeri grows very well with us here, with the new growth coming early, and maturing in all its glory before the hot summer sun arrives. For those who garden in areas with warm to hot summers, I think R. falconeri is the species to try, amongst the big-leafed ones. There is a much greater chance of growing it to near perfection than say, R. sinogrande which comes into new growth just about at the beginning of summer. I cannot grow the huge leaves on this one in our present garden in the same way they grew at the higher elevation in our old garden. They need an almost perpetual fine mist as the new growth emerges. However, with R. falconeri we are blessed with whorls of leaves three feet across, backed with beautiful indumentum. Maybe those in cooler regions could experiment with the species coming into late growth such as R. sinogrande .

All growers of species will delight in growing the exotic Maddenias ranging from the huge flowered R. nuttallii , dalhousiae and lindleyi (some would consider these the pick of the genus), to those not quite so widely grown including R. supranubium (now a synonym of R. pachypodum ) and taronense (now synonymous with R. dendricola ). Favourite among these has always been R. ciliicalyx , to me one of the most charming of this group of species in all its forms. In our climate most of the Maddenias appreciate a little protection from the hottest summer sun or can suffer some leaf scorch. Perfume is an added attraction in many of these species.

Triflora and Cinnabarina subsections both contain species to form fascinating groups for woodland planting, especially nice are groups of R. augustinii . I have always thought that the graceful triflorums are a "must" in all rhododendron collections, so too the elegant cinnabarinums. In more open gardens these two groups will grow more densely and perhaps flower more freely, but may lose a little of the willowy charm.

The more formal Arborea subsection plants make outstanding lawn specimens, given ample room to develop, and R. arboreum ssp. campbelliae (now included in R. arboreum ssp. cinnamomeum var. cinnamomeum ) excels in such a position. A delight to all who see it in full flower early in the season, this one flowers from quite a small size and over a long period. An added bonus, of course, comes after the beautiful pink flowers, when the new foliage flaunts its cinnamon indumentum on its upright spring leaves.

One often hears the complaint that species take too long to grow to flowering size. I would dispute this, there are many which take a shorter time to flower than many hybrids.

In the meantime, many species such as those in the Neriiflora, Pontica and Taliensia subsections which may take a long time to reach flowering size, reward the discerning gardener with magnificent foliage, particularly in spring, when the young leaves unfurl. Who could desire more fascinating plants than R. mallotum , bureavii and elegantulum , to name but three of the glories of these subsections. Think, too, of the sheer magnificence of R. campanulatum var. aeruginosum with its brilliant glaucous blue new leaves which always stops the visitor in his tracks!

Pause to reflect on the incredible journeys, as chronicled by the intrepid plant hunters, particularly earlier in this and the last century, when travelling was considerably more hazardous than it is for today's explorers. We should pay homage to those greats who gave their all, and, for some, life itself in order to enrich our gardens. It certainly adds to the interest in our species, if we read of their first discovery, or perhaps subsequent discoveries, and thereby gain some insight to their natural habitats.

In the vast array of species with some lost to cultivation awaiting to be rediscovered and others no doubt awaiting first discovery, there is surely something of appeal to everyone, from the big-leafed ones already mentioned right down to the tiny dwarfs hailing from the wind swept high alpine moorlands. What delightful creatures these tiny wildings are, and highly prized by alpine enthusiasts for their rock and peat gardens!

One of the more fascinating aspects of species growing appreciated by the keen gardener is the collection of species under the original collectors' numbers. One appreciates, for example, a plant of R. keleticum R. 58, being Rock's form (now classed as a subspecies of R. calostrotum ), or R. radicans F. 19919, being the Forrest form (now classified as R. calostrotum ssp. keleticum ).

In my opinion it would seem that if we accept the new classification in totality, in due course many treasured species will finish up in oblivion to the obvious detriment to our gardens as a whole and to the future generations of gardeners. It will incidentally add more confusion to the increasing number of synonyms. I guess that many of us are still inclined to retain use of outdated names for some of our favourite species!

Another species under its collector's number is a great favourite, R. racemosum 'Rock Rose' R. 59578. It is so very different from most other forms of R, racemosum . This one is quite a tall grower for a species that one is inclined to consider a dwarf. My plant was imported as quite a small one in 1979 and now is over 5' tall. It is aptly named, the flowers being a delightful rose colour. The growth and flowers being in great contrast to the well-known dwarf Forrest form F. 19404.

It is not always easy to obtain these species under the collectors' numbers, but the keen gardener will always try to seek them out as the associations do really mean a great deal to the thinking person. Surely one of the great satisfactions of growing rhododendrons is to read about their discovery and to know that perhaps that particular discovery is growing happily in one's own garden.

To some people growing species has an elitist flavour, I would not agree with this, to me it seems to have the flavour of recognition of what nature has evolved over perhaps millions of years. There would seem to be a myth that all species are difficult to grow, this is, of course, nonsense - most are quite easy, if one takes into account their particular requirements.

Admittedly, after all, there are some that would tax the persuasive powers of the most dedicated gardener. One who would readily agree that the old saying of "a hybrid is two species spoiled" is nonsense. One need only look at the demanding and difficult dwarf species, R. ludlowii . Yes, some fortunate people do not seem to have any difficulty in growing it thanks to their particular microclimate, whilst others struggle for years in despair. Yet this one has been used to parent a race of most exquisite dwarfs, quite hardy, easy to grow and magical in their ethereal beauty. So of course, one would not discard hybrids.

All of us who are dedicated species growers must always remember that the taxonomists are quite likely to tell us that some of our treasures are not species after all, but merely natural hybrids! Look at the fate of some of those which used to be included in the old Lapponicum series - R. edgarianum , lysolepis and verruculosum - now all considered hybrids. But then again, it all depends on whose opinions you follow!

For those who delight in delving a little further into the sometimes hidden attributes of their species, I would suggest that new dimensions can be easily opened up by the acquisition of a little, very inexpensive hand held pocket microscope. My little one with a built in light and a magnification of x 30, with adjustable focus, has given me a great appreciation of some of those hidden qualities. To see the rather ordinary (to the naked eye) scales on R. keiskei leaves transformed to beautiful golden craters, and the furry undersides of the leaves of R. pendulum transformed into a wild forest takes one into another new world! A world which we can all enjoy.

Felice Blake is a regular contributor to the ARS Journal. She and her late husband have established a fine collection of rhododendron species and hybrids.