Tag Archives: plant breeding

The plant breeder’s garden

“It’s very white out there,” he said

“It is very white out there,” Mark observed. We were standing in the roller door of our large shed, sheltering from another rainy squall and looking out to the new summer perennial gardens. The photo doesn’t fully convey the white experience. The row of Fairy Magnolia White, Camellia yuhsienensis and Mark’s hedges of michelia seedlings were all in view. Mark was envisaging a carpet of snowdrops at ground level as well, even though they are but a fleeting delight. I was looking at the michelia seedlings.

Mark has planted two sides of the new garden area in michelia hedges. Technically – in accurate nomenclature – these are all magnolias now but we continue to use the earlier term ‘michelia’ for the sake of clarity. When we say ‘magnolia’ here, we are almost always referring to deciduous magnolia trees so it is confusing to include the world of evergreen michelias which also feature very large in our lives at this time of the year.

Some of the seedlings are simply gorgeous but won’t be named

When planting seedlings, it means every plant will be different. For the largest length of visible hedge, he planted out one particular cross that had not come out as he hoped because very few were coloured. The nature of the parentage means that they will flower well, not grow out of control and be suited to clipping but they will never have the precision of planting a row that is all one clone – in other words, identical to each other. Mark likes seedlings for mass plantings because it adds interest to have them all similar but not identical.

Others are pretty on their day but floppy blooms don’t cut the mustard

I paced along his hedging, estimating how many individual plants there are. Getting close to 200, was the answer, planted at about 30cm spacings because we want a quick hedge that can be trimmed as required. Each individual plant in bloom is lovely on its day but some are lovelier than others. However, none will be named and put into commercial production. Mark has already named Fairy Magnolia White and Fairy Magnolia Cream and he won’t name any more white or cream ones unless there is something that is radically different or a major improvement. So these are ours to enjoy alone.

Heading into pink 

Part of a breeding breakthrough in colour but not good enough to select

At one end, there are about three different pink-toned varieties which are something of an oddity in amongst the cream and white majority. Again, he has already named Fairy Magnolia Blush in this colour range so they will just stay as a quirky aberration in the hedge at flowering time. We are okay with quirks.

Hardy michelias are basically white or cream. While there are new tropical species still being discovered and some of those show more colour, Mark has no interest in trying to breed with them, even if we could get them into the country to work with. Most of the michelias are not overly hardy at the best of times and he has been trying to get hardier selections (will they grow well and flower consistently in places like the UK, is one of his measures) without introducing more tropical genes. But he has managed to get as far as pinks, purples and primrose yellow by ever more complex crosses using the material he has available.

From white through to pinks and purples with a few heading into pale yellow –  blooms from the breeding programme

I see it was four years ago that I set out to pick a representation of single blooms from his seedlings to show the range in colour, flower size and shape that he has reached in what is predominantly a white or cream plant genus. While he has continued to flower more since, this photo remains a fair summary. We have selected three new ones that are currently in propagation and performance trials for probable release but there is a whole lot more to selecting a plant than the just flowers. My lips are sealed as to what makes these three worth singling out until we are further down the track of commercial trials.

Fairy Magnolia Cream just coming into flower

In case you are interested in what goes into selecting a plant (or you want to name something you have found), off the top of my head, the checklist includes the following:

  • Is it either distinctively different or a major improvement to similar plants already on the market? (This is arguably the single most important criterion).
  • Are there plenty of flowers? How long is the flowering season (some can be a short flash in the pan)? Does it flower consistently well every year?
  • Are the blooms reasonably weather hardy?
  • If it is scented genus, are the flowers fragrant?
  • Do the blooms age gracefully and fall cleanly?
  • Is the foliage as good as the flowers?
  • Is the foliage in proportion to the flowers?
  • Where do the leaf buds open from? In the case of michelias, does it just set leaf buds on the tips (in which case it will look leggy and bare very soon) or does it set leaf buds right down the stem.
  • Does it ever defoliate in a wet spring (a feature of Magnolia laevifolia formerly known as Michelia yunnanensis)?
  • What is its performance like as a garden plant , not just grown in a container? It takes several years to make this assessment. In the longer term, will it stay a garden-friendly size? Does it take pruning, trimming or clipping well?
  • What is its international potential? How is it likely to perform in more extreme climates?

Only then do the propagation trials start. There is no point at all in selecting a plant that is difficult to propagate, where the percentage of cuttings that do not set roots is too high, where plants *whiff off* – Mark’s phrase meaning die – during production, or where very particular propagation and growing techniques are required for success – growers just do not want to put the time and expense into growing plants that are unreliable or too picky.

New releases used to be the life blood of our mailorder business. Some selections stood the test of time, others not so much. At least all the magnolias have proven to be worthwhile. It is the vireya rhododendron selections and a few of the camellias that have fallen off the Jury plant wagon. These days, we get a new plant through the initial selection and then we hand it over to our agents to manage through final trials and then getting it to market.

It is a long path to getting a new cultivar onto the market. But in the process, we get a lot of unique plant material to use in our own garden.

Magnolia doltsopa syn Michelia doltsopa – a selection released as ‘Rusty” by nurseryman, Peter Cave. Pretty flowers but showing typical floppy tendencies of this species and the original plant in our park is massive.

A touch of Tikorangi around the world

We are generally accustomed to seeing Jury plants growing in different parts of the world, though sometimes it generates a special thrill. A UK friend sent this photo of Magnolia Felix Jury in bloom at The Garden House in Devon last week. We had seen this particular tree growing strongly several years ago but it was summer, so in leaf, not bloom.

It takes time for a magnolia to prove itself, particularly across a range of different climates. Magnolia Vulcan has never really performed in cooler climates because it loses its flower size and blooms more in muddy-purple tones than in the deep claret-red that sets it apart here. There is always apprehension as to how other deeper coloured cultivars will perform in much harder conditions than we have. Early blooms on ‘Felix Jury’ in the chilliest climes of Northern Europe show that it retains its flower form and remarkable size, but the colour can bleach out – albeit to prettier shades than the muddy ‘Vulcan’. Whether that colour will deepen as the plants mature (which is what happened here over a period of years) remains to be seen.

This made it a special delight to be sent the photo of The Garden House specimen, showing good colour, good size and the correct flower form.

Even I found it touching to see Mark’s delight at the specimen of Magnolia Felix Jury growing a few doors up from where our daughter lives in Canberra. He felt it was like having a touch of Tikorangi in her street. Canberra is not exactly Magnolia Central so if ‘Felix Jury’ blooms as well there as at The Garden House, it will be a showstopper. The house owners were a tad surprised when I knocked on their door to ask if I could take photos and explained why. They also had Mark’s Fairy Magnolia Blush growing to the immediate left of the umbrella. Nothing illustrates the stark difference in climate to here more than an astroturf lawn.

When near enough is not far enough

012It being autumn, ‘tis the season of sasanqua camellias here. Ever since camellia petal blight arrived to wreak havoc on the later flowering japonicas, we have been a great deal more appreciative of the sasanquas. What they lack in flower form, they make up in performance.

Gay Border on the left, Navajo to the  right

Gay Border on the left, Navajo to the right

On a grey and somewhat bleak day, I thought to entertain myself with photographing the flowers but became sidetracked onto comparisons. When we had our nursery in full production, Mark would regularly make calls as to which cultivars we would propagate and sell. Would it be Navajo or Gay Border? We chose Navajo. It is not just the flowers that are the deciding factor. The habit of growth, foliage, size, performance and ease of propagation and production were also considered although the decisions were often a little ad hoc. When it came to Sparkling Burgundy and Elfin Rose, we chose the latter because its foliage looked better.


Sparkling  Burgundy left, Elfin Rose right

Sparkling Burgundy left, Elfin Rose right

We felt that it is not helpful to a customer to look at a range of plants with very subtle differences. “The man on the galloping horse” test, Mark calls it – the differences should be obvious, not just subtle variations. As far as we were concerned, we were professionals and customers had a right to expect us to do some filtering in selections and to pick good performers.

When it comes to naming his own cultivars from his breeding programme, Mark is hugely more rigorous and restrained. A new release has to be significantly different, distinctive or a major improvement. He has only named four of his own deciduous magnolias so far and that is out of many, many hundreds – maybe into the thousands – of seedlings he has raised. This restraint is somewhat unusual in the world of plant breeding.

Honey Tulip top left with other named cultivars. Might we have seen this as a breakthrough in flower form?

Honey Tulip top left with other named cultivars. Might we have seen this as a breakthrough in flower form?

When we released Magnolia Honey Tulip, we received an email from an overseas self-appointed expert acknowledging that Mark was extremely – excessively, some may say – restrained about the new selections that he named and released but he should not have released a yellow magnolia. The world has enough yellow magnolias already, he loftily told us. Right-o then. We knew what he meant – there are many yellow magnolias named which all look very similar, but apparently it had not occurred to him that Mark, with his self-imposed restraint, may actually have managed to breed one that was a breakthrough and very different. We did not reply.

Anybody can raise seedlings of Black Tulip but are they then all worth naming? We think not.

Anybody can raise seedlings of Black Tulip but are they then all worth naming? We think not.

A plant breeder, by our definition, does more than just raise open pollinated seed. Not so the gentleman who visited us (again from overseas). He loved Mark’s Magnolia Black Tulip which sets seed. So he raised a whole batch of seed and spawned a whole lot of similar looking flowers which he then named and insisted on showing Mark all the photographs. None looked to be distinctive, a breakthrough or an improvement. They were just subtly different, as seedlings usually are. That sort of willy-nilly approach is not helpful to the plant and gardening world but we see it often.

That is why we have never coveted a National Collection – of anything really. The UK is very big on national collections. The parent website states:

“Plant Heritage’s (NCCPG’s) mission is to conserve, grow, propagate, document and make available the amazing resource of cultivated plants that exists in the UK….

Our main conservation vehicle is the Plant Heritage National Plant Collection® scheme where individuals or organisations undertake to document, develop and preserve a comprehensive collection of one group of plants in trust for the future.”

Camellia brevistyla left, microphylla right. They look mighty similar to us.

Camellia brevistyla left, microphylla right. They look mighty similar to us.

It is one thing to collect species – that is important for biodiversity and many are endangered in the wild. Mind you, we remain unconvinced that Camellias brevistyla and microphylla are actually different species. It looks more like seedling variation to us.

"For I have seen the national rhubarb collection"

“For I have seen the national rhubarb collection”

Also the compilation and maintenance of a wide genetic pool is important when it comes to crops like fruit and veg. “For I have seen the National Rhubarb Collection”, I tweeted when we visited Wisley. It seemed such a random and esoteric plant to collect, which is not meant in any way to deride its worth. And it was certainly a beautifully maintained collection.

But a National Collection that takes in many named hybrids? We have seen too many inferior and indistinct hybrids named to ever want to start a collection of any plant genus. We would rather have plants that are selected on individual merit in our garden.

Plant collecting is like stamp collecting, Mark explained. The search for a particular named cultivar may be challenging, rewarded by the thrill of acquisition. Whether the plant was actually worth acquiring – whether it warranted naming in the first place – becomes irrelevant.

Postscript: we don’t like to dwell too much on the travesty of our Cordyline Red Fountain and the ring-in Cordyline Burgundy though this was not, we think, motivated by misplaced breeder pride but by much baser motives indeed.

Know thine species

The show dahlia

The show dahlia

You can quite easily live out your gardening days without ever worrying about species and hybrids. Indeed you can, but as with most activities, many people will find that the more they know, the more they enjoy what they are doing.

At its simplest level, species are the natural form of a plant in the wild. And all plants originated somewhere in the wild.

Hybrids are mix of two different species in the first instance and after that they can quickly become a mix of many different species and resulting hybrids getting ever more complex genetic makeup. There is no value judgement in the rights and wrongs of that. Sometimes these hybrids occur in the wild without any human intervention (usually referred to as “natural hybrids”). Often it is done deliberately to try and improve plants.

A variation on controlled hybridising is line breeding – raising many seed from a plant and selecting only the very best with which to continue. Then seed from those best plants is raised time after time until it shows stability. Seed can be extremely variable and this form of line breeding is trying to edit out the less desirable aspects over several generations.

It happens all the time with edible crops. Think how much sweet corn and kiwifruit have changed over the years. The original, wild collected species of edible crops are often poor shadows of what we have now in terms of yield, reliable production, ease of handling and palatability.

It is not always true, of course. Sometimes commercial imperatives have seen us saddled with inferior tasting product – tomatoes are a prime example. And there are concerns about the loss of the wild species which are important to maintain the gene pool for food crops.

As far as ornamental plants are concerned, most of us will have gardens which are a mix of species and hybrids. There are no hard and fast rules although I have met a fair number of gardeners in my time who parade a collection of species only as a badge of status.

Species Camellia gauchowensis

Species Camellia gauchowensis

Some species have a simple charm which is lost in their showier hybrids. Others are nondescript in the extreme. Some highly desirable species are simply damn difficult to grow whereas the hybrids bring new vigour which makes them much more rewarding garden plants. Sometimes there are species which make splendid garden plants but they can be overlooked because their names are not appealing. Camellia gauchowensis has been the standout star of that family here recently and why anybody would grow the likes of Mine No Yuki instead of C. gauchowensis, I don’t know.

We have been revisiting the camellia species as we pick over the best options in the face of the devastating camellia petal blight which has so affected many of the hybrids we grow. It is not that the species don’t get it. It is just that some of them have less susceptibility and have other good characteristics which are worth looking at. More on this in the future.

Show blooms, no matter which plant family, often tend to be over-bred hybrids which are but distantly related to original species. Dahlias which are too heavy to hold their heads up without staking, bizarre daffodil forms, overblown cyclamen or chrysanthemums, enormous begonia flowers – anything that is bigger, allegedly better or a novelty genetic freak.

Named hybrid aster at top, self sown seedling at bottom

Named hybrid aster at top, self sown seedling at bottom

But controlled hybridising can also give us garden plants which are hugely better performers. You can see in the photograph of asters that the abundance of blooms at the top are from a named hybrid whereas the few poor specimens at the bottom are from a self sown seedling which has probably reverted closer to how the original species looks.

Hybrid arisaemas for our own garden

Hybrid arisaemas for our own garden

I am of course married to a plant breeder who is driven by the desire to create better performing garden plants. Sometimes it is just to get plants which will grow better in our garden here. His work with arisaemas is of this ilk. Many of the desirable arisaemas are a battle to grow in our conditions with insufficient chill and they simply don’t come back a second year. By hybridising two different species, he can get hybrid vigour which means they are much more reliable and stronger growing.

Other plants may be hybridised to look for new or improved characteristics – extending the colour range, reducing the impact of disease, getting more compact growth, better floral display, a longer season, sterility (to avoid unwanted seeding) or bringing the best features of different hybrids together in one plant. There are many reasons to hybridise and one of the final tests before selecting a new cultivar for release is to measure it against both the originating species and the actual parent plants. If it is not a significant improvement, then it won’t get released on the market.

Hybrids have their place in the ornamental garden and in the edible garden. But in a world which is squeezing the natural environment in every way possible, we need to retain the original species for reasons of ecology and bio-diversity. The more people who understand the difference the better – even more so if they can move away from the modern “green” cliché that says the original species are, by definition, better. They are not, but they are important.

First published in the Waikato Times and reprinted here with their permission.

The Jury vireya legacy – first published in the RHS Rhododendrons, Camellias and Magnolias 2012 yearbook

The original plant of R.macgregoriae, collected by Felix in New Guinea

The original plant of R.macgregoriae, collected by Felix in New Guinea

Back in the 1950s when Felix Jury first became interested in vireyas, they were pretty much unknown in New Zealand with few enthusiasts internationally.

When Felix started raising seed and trying controlled crosses, he was just after anything that was new and therefore interesting. There was so little raw material to choose from in those early stages. He named maybe a dozen and with the passage of decades, about four of that dozen have stood the test of time very well and may still be around in another thirty years’ time. Unfortunately, the finer details on his crosses were never recorded so it is not possible to state with certainty which were Felix’s own crosses and which came from seed sent to him from overseas and were therefore just raised and selected by him. We know that the Australian, Tom Lelliot was particularly generous with seed and there were others from that country.

Golden Charm

Golden Charm

In 1957, Felix went plant collecting in the highlands of New Guinea. He brought back a few interesting plants. Ficus antiarus is still the most asked about tree in our garden. Schefflera septulosa is one of the most beautiful members of that plant family you will ever see. His form of Rhododendron macgregoriae is still rated as one of the best in circulation and, astonishingly, the original plant is still surviving. This is an achievement because vireyas are not noted for being long-lived in our climate. It was that plant of R. macgregoriae which gave rise to one of Felix’s best cultivars – Golden Charm (R.macgregoriae x Princess Alexandra). We still rate it highly after several decades. The foliage is dark and glossy, the new stems are red, the habit is compact and healthy and the many flowers, while relatively small, are in good sized heads and attractive apricot to orange tones. It is also relatively hardy.



With the benefit of hindsight, we now wonder whether Felix’s other two notable R. macgregoriae hybrids, Buttermaid (R.aurigeranum x R.macgregoriae) and Orangemaid (R.laetum x R.macgregoriae) might not in fact be Lelliot seed, raised and selected by Felix. Alternatively, he may have been sent pollen. Mark is not at all sure that Felix had R.aurigeranum at that stage and he is sure he did not have R.laetum. The R.macgregoriae parentage shows dominance in both the flower form and colouring of these selections but hybrid vigour makes them more reliable and tidier garden plants. Queen of Diamonds (R.viriosum x R.macgregoriae) was indubitably Felix’s own cross, a pink version this time but rather too tall and leggy to be of great merit. [Apparently R.viriosum was misidentified for 70 years as R.lochiae. Most records use the R.lochiae name when it appears that they are all in fact R.viriosum. I will defer to those with a great deal more expertise in this matter and have according changed to using R.viriosum.]

Satan's Gift planted by the Schefflera septulosa

Satan's Gift planted by the Schefflera septulosa

Satan’s Gift (R.konori x R.zoelleri) and Silken Shimmer (R.konori x Dr Herman Sleumer) were selections from Australian seed, raised by Felix. These were spectacular for their day, being big and lush, colourful and fragrant. Satan’s Gift is the stand-out plant which has passed the test of time and is still a wonderful performer. The name amuses us. Felix was a completely non-religious man and to him, Satan merely evoked hot colours. Over the years, more devout nurseries have clearly had a problem with the name and this cultivar has been marketed variously as Jury’s Gift, Satin Gift and, best of all, Santa’s Gift. One wishes nurseries would understand that it is fine to reject a plant because of ethical issues with the name, but it is not acceptable to rename it willy nilly.

Cherry Pie

Cherry Pie

Felix was very taken with the big, scented blooms of R.konori and his own hybrids were the pink Cherry Pie, red Hot Gossip – both sister seedlings of a viriosum hybrid x R. konori – and Lipstick. Cherry Pie is particularly lush and has good bushy, spreading growth along with a good flower (though much of the scent has gone) and we still rate it as a good garden plant.

Red Rover (R.viriosum x R.javanicum) is another of Felix’s early hybrids that we continue to rate for its bushy growth habit, healthy characteristics and plenty of good red flowers in a mid-size. However his R.jasminiflorum hybrid called Lullaby has dropped off the radar now and, while a good performer, Lulu (unknown) has probably been superseded by modern selections with more flowers to the truss.

By the time Mark started hybridising vireyas, there was a veritable explosion of recently discovered species and newly imported species becoming available. He collected every single one he could lay his hands on at the time and propagated a few to distribute to collectors. Our nursery records show that we produced over 60 different species at that time, and very difficult most of them were too. The death rate in the species was far higher than in the hybrids, both in the nursery and when planted in the garden. It was with some relief that we decided after a few years that the few collectors in the country (there were probably only 5 or 10 of them) had everything we held so we stopped feeling obliged to produce them. Similarly we decided that it was not critical to keep every species represented in the garden. We have never coveted a national collection of any plant genus because we would prefer to garden with plants which justify their position as being garden worthy. Only some of the vireya species perform well for us – we would be sorry to lose varieties such as R.himantodes, R.goodenoughii, R.taxifolium, R.hellwigii, R.macgregoriae and R.konori but many of the other species are either too difficult for us to keep going, or not worth the effort (R.inconspicuum, we have always felt, was particularly well named).

Sweet Cherry

Sweet Cherry

So Mark had a much bigger plant palette to work with and this included an ever increasing number of new hybrids as well as the species. Vireyas were suddenly a fashion plant in New Zealand. They were seen as a wonderful alternative for warmer areas of the country where the hardy rhododendrons do not thrive. Added to that, in a country where we would like to be tropical but aren’t, vireyas fitted that exotic look and often obliged by flowering throughout the year. From being an unknown plant family with no market at all, they were a gardening sensation for a few years in the nineties. Fashions change and vireyas are no longer as popular as they were – they are somewhat harder to keep alive, let alone looking good, than many people realised. But in those heady days, there was an insatiable demand for new varieties which had large luscious blooms with heady fragrance and large, heavily felted foliage. Unfortunately, this sometimes meant using breeder parents which, with the passage of time, have not proven to be particularly resilient in our climate.

Mark was also keen to extend the flower form of vireyas into full trusses which more closely resemble the hardy rhododendrons. Many of the species and early hybrids are quite sparse in their flowering and have few flowers to the truss. He also wanted to explore what could be done with colour.

Mango Sunset

Mango Sunset

With the benefit of twenty years experience, he has gone full circle and come back to the point his father reached earlier – a conclusion that it is more important to produce healthy plants which stay alive, with compact growth and masses of flowers as top priorities. More hardiness and less flash and dash, one could say. This tends to mean sacrificing individual bloom size, foliage size and often fragrance. It may end up that his R.macgregoriae hybrid, Mango Sunset, proves to be one of his best. While he achieved the much fuller truss, he was looking for, it is just a good all round performer without being spectacular.



Market demands meant Mark made the same mistakes as many other vireya breeders – selecting new cultivars on the beauty of their blooms and on initial performance as a nursery plant. The test of longevity rests, for us, on long term health and performance as a garden plant. More than we would wish have fallen by the wayside. Candy Sunrise (R.konori x Halo series) had beautiful, big fragrant flowers with good colour but was very susceptible to phytopthora. Ditto the red Sweet Cherry (R.konori x R.hellwigii) – wonderful as a garden plant but not easy in the nursery, Strawberry Fields (Satan’s Gift x R.brookenaum) – gorgeous big red flower but leggy growth over time and inclined to die, Orange Sparkles (R.retusum x R.macgregoriae) and cute little Jellybean (Red Rover x R.stenophyllum). Frosted Candy, another of the R.konorii x Halo series hybrids, is performing very well as a large garden plant (now two metres plus which is large for a vireya) and it has huge blooms, but again is difficult in the nursery with an unacceptably high death rate from phytopthora.

Jaffa (Halo series x R.javanicum) is in the right direction for a full truss. There are now up to 15 large blooms per flower head (which is a big increase from the 2 to 5 range of many of the species and early hybrids) and a good, strong orange combined with large, lettuce green foliage. It is more frost tender and sensitive than the tougher cultivars (which tend to be those with R.macgregoriae, R.viriosum or R.saxifragoides in their parentage). It certainly has the right tropical look and is a better nursery plant than many.

Pink Jazz

Pink Jazz

Pink Jazz (R.konorii x Halo series) is another splendid large grower with enormous blooms – bright pink with a central star of cream and scented too. It also has the stand out feature of deep maroon new growth and even the old foliage keeps the burgundy tint. It is not easy as a nursery plant and it is too big for many gardens, but the plants we have in our garden are standing the test of time. We have a special fondness for this one. Mark rarely names plants after people, but this one is for our older daughter who, in her teens, was called Jazz by many friends and who nursed a penchant for wearing hot pink.

Mark has always been lukewarm about Peach Puff ([R.phaeopeplum x R.leucogigas] x R.viriosum selfed) because he regards the pastel peach colouring as insipid. It was an interior fashion colour a decade ago and I still find it very pretty. Again the truss is satisfyingly full with big blooms, good scent and felted foliage.

Sweet Vanilla

Sweet Vanilla

Of that type of larger flowered, scented hybrid, Sweet Vanilla ([R.leucogigas x R.viriosum] x Silken Shimmer) is probably the best garden plant for fragrance. Its flowers, while not huge, are a good size, opening soft pink and fading out to cream. This is one plant which garden visitors regularly ask about when in flower – always a good indicator of showy performance. Sherbert Rose (Hot Gossip sister x R.herzogii) matches Sweet Vanilla for scent and it is very floriferous but the small tubular mid pink blooms simply aren’t showy enough for most people. We still like it because we don’t want only big showy or blowsy vireyas in the garden, but we stopped producing it commercially because scent alone was not enough to sell the plant.

Practical Matters:

Preparing vireya cuttings - wound both sides

Preparing vireya cuttings - wound both sides

Vireya rhododendrons must rank amongst the easiest of the woody plants to propagate but one of the hardest to produce commercially. Neither are they bullet proof as garden plants. As long as you have firm, green material, it is easy to get cuttings to root. You don’t even need rooting hormone. In fact it is so easy that we routinely showed customers how to take autumn cuttings so they could have back up plants lest their specimen get taken out by a hard frost or wet roots. The one critical issue is to remember to have a generous sized cutting and to take the sliver off two sides of the stem (wounding). Vireyas put their roots out from the exposed cambium layer and having two wounds gives a more balanced root system and therefore more stability. It is keeping them alive after rooting which is the tricky part, especially in nursery production. Vireyas are not only frost tender and deeply intolerant of wet feet (sodden root systems), but they are vulnerable to pretty much every strain of phytopthora and a fair range of other diseases common in nursery production. In the wild, many of the vireya species are epiphytic or semi epiphytic which is an indicator that their roots need open conditions. This is what fits them to a role as permanent pot plants though they appear to last better in pots which are more permeable (terracotta or wood) than in containers which are impermeable (glazed pottery or plastic) and dependent for drainage on one or two holes in the bottom. When producing commercial runs of vireyas, we maintained a rigorous spray programme to keep disease at bay. Even so, we tolerated a far higher mortality rate in nursery plants than we would in any other crop. We have always produced them outdoors, under protective shade cloth and overhead irrigation – identical conditions to most of our nursery crops.

Vireyas tend to put on a lot of top growth, supported by small, inadequate root systems (an indicator of their epiphytic origins), and new growth is often very soft and brittle. As nursery crops in our climate, they grow very rapidly at all times of the year and it is possible to get a saleable plant through in half the time of a hardy rhododendron, but they are correspondingly more vulnerable to damage by mishandling and disease.

Vireyas used in a garden border

Vireyas used in a garden border

We are blessed with a climate which enables us to use vireya rhododendrons as garden plants. We are not entirely frost free so we use them on the woodland margins where temperatures may get cool but never cold enough to cause significant damage. Any frost at all can burn the most tender varieties which includes anything with R.leucogigas, R.konorii, R.hellwigii and sometimes even R.laetum in the breeding. The hardier types will take two or three degrees of frost without damage but more than that can be a problem. Get it up to five degrees of frost and plants can be killed stone dead. The beauty of vireyas as garden plants is that they do not have a set flowering season so if you have sufficient numbers, there are always plants in bloom – even in the depths of winter. Added to that, they are tolerant of hard pruning so easy to renovate. Even when cut back to bare wood, most will force out dormant leaf buds from old wood and can be bushy and fresh again within a matter of months, even if it takes longer for them to set flower buds. It is a misconception that vireyas are all tropical plants. While natural habitats are often in the tropical latitudes, they are in elevated sites which cool the temperatures.

With their climatic limitations, vireya rhododendrons will never have the geographic distribution of hardier plants and, no matter how good the hybrids, they are unlikely to achieve international standing. There is a long way to go yet in breeding reliable cultivars which are likely to stand the test of time but it is certainly interesting to have been in from the early days on the development of new selections and Mark will continue to work with them here, albeit on a rather casual basis.

A promising  lemon seedling - the breeding continues

A promising lemon seedling - the breeding continues

The first instalment of this series was the 2011 article on Jury rhododendrons.