Rhododendron ‘Princess Alexandra’

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Rhododendron ‘Princess Alexandra’ is a vireya (tropical rhododendron) cultivar, the result of a backcross between the very first vireya hybrid, Rhododendron ‘Princess Royal’ (R. jasminiflorum x R. javanicum), and its parent R. jasminiflorum. It was registered by the famous nursery of J. Veitch & Sons in 1865, from which we can deduce that it was named in honor of Princess Alexandra of Denmark who had married Prince Albert Edward, the future King Edward VII, two years earlier.

Some plants remain consistently popular, while others go in and out of style. Vireyas definitely fall in the latter category. R. jasminiflorum flowered in England for the first time in 1849, and over the next fifty years or so, several hundred vireya hybrids were registered, mostly by the Veitch nurseries. Along with orchids and other tropical plants, vireyas graced the conservatories of the Victorian upper class, but their popularity was eventually eclipsed by hardier Rhododendron species which didn’t need an expensive heated greenhouse. It wasn’t until the second half of the twentieth century that an influx of newly discovered species made vireyas and their hybridization popular again. This second wave of cultivation occurred in places where vireyas could be grown outside–New Zealand, Australia, coastal California, Hawaii–and hybridizers focused on species from the mountains of Malesia (the biogeographic region encompassing Peninsular Malaysia, the Malay Archipelago, and New Guinea) that thrived in cool, but not freezing, weather.

In the the years between the first and second periods of vireya popularity, two world wars and a great depression wiped out many of the old collections of tropical plants, and fewer than ten of the Victorian hybrids survive today. I find it amazing that the R. ‘Princess Alexandra’ in my greenhouse is essentially the same plant that grew in the Veitch nurseries. It has been propagated by cuttings and traded among enthusiasts for more than 150 years.

I love to grow vireyas, but unfortunately most vireyas don’t love North Carolina. Although vireyas come from the tropics, most species grow at high altitude, up to and even above the tree line. The montane species–and hybrids dominated by those species–are weakened by our long, hot summers and tend to die suddenly after a few years. I have the best long-term success with the relatively few species that grow naturally a lower altitudes, and it is exactly those species, plants like R. jasminiflorum and R. javanicum, that are the parents of the Veitch hybrids. I’d love to grow more of the old survivors, if only I could find them.

So, if anyone knows where I can obtain cuttings of Rhododendron ‘Ne Plus Ultra’ or R. ‘Triumphans’ in the United States, please let me know.

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Six on Saturday #66 (May 22, 2021)

After one of the mildest and wettest winters on record, we have had one of the driest springs. This week, the switch flipped to “summer” and with the increasing heat and humidity, we can perhaps hope for a thunderstorm or two.

Here is some of what is growing and flowering in the greenhouse and garden this week.

1. Medinilla ‘Royal Intenz’

Medinilla_Royal-Intenz

Beautiful plant, silly name. This new cultivar is apparently a hybrid, but it’s not clear what species are in its background. Definitely Medinilla magnifica, because M. ‘Royal Intenz’ looks rather like a very intensely colored, compact M. magnifica. The abstract of the plant patent simply refers to its parents by ID number, not species or cultivar names, and there doesn’t seem to be any way for me to find out exactly what I am growing. It’s somewhat annoying.

In any event, M. magnifica and related species–and by extension M. ‘Royal Intenz’–are epiphytic shrubs from the Philippines which adapt well to cultivation in a warm greenhouse or bright, humid windowsill. Logee’s offered M. ‘Royal Intenz’ briefly last year, and I’m glad I got an order in before they sold out.

I’m starting to see some fungal spotting on the foliage, perhaps due to water dripping from overhead Nepenthes plants. I think it’s time to move it to a brighter and drier spot in the greenhouse, or perhaps outside for the summer.

2. Pearcea rhodotricha

Pearcea rhodotricha flowers

Pearcea rhodotricha is a gesneriad from Ecuador with flowers that are probably the closest that I have ever seen to true black. Adding to its overall bizarre appearance, the stems and undersides of the leaves are densely covered with red hairs (hence “rhodotricha”) not unlike those of a tarantula.

A picture of the stem of Pearcea rhodotricha

3. Corytoplectus cutucuensis

A picture of the berries and foliage of Corytoplectus cutucuensis

Another Ecuadorean gesneriad, Corytoplectus cutucuensis has insignificant yellowish flowers. It’s the shiny black berries, sitting within long-lasting red bracts, and the beautifully variegated foliage that make it worth growing. Both this species and the previous are easy to grow from cuttings and appreciate a shady humid environment.

4. Encyclia Gail Nakagaki

Flowers of Encylia Orchid Jungle

Encyclia Gail Nakagaki is Encyclia cordigera x Encyclia alata (see below), and you can clearly see its parentage in its flowers. E. cordigera var. rosea gives the beautiful purple color and hooked tepals while E. alata contributes the striped lip and pale tepal bases. The fragrance of this orchid hybrid is fantastic.

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An old photo of an Encyclia alata in my collection

5. Tradescantia ‘Osprey’ (hybrid spiderwort)

Flowers of Tradescantia 'Osprey'

I suppose I ought to have at least one outdoor flower in my Six. ‘Osprey’ is a Tradescantia x Andersonia cultivar, but its pastel flowers are much more restful than the hot color of ‘Sweet Kate’ or ‘Concord Grape’ (see photos 2 and 3 of Six on Saturday #44). For some reason, it isn’t readily available at local nurseries, and I had to mail order this plant. It has doubled its size in a year, so maybe it will be large enough to divide and spread around the garden this autumn.

6. Ipomoea batatis (sweet potato)

sweet_potatoes

Slips from some ‘Beauregard’ sweet potatoes that we grew last year are almost ready for planting. Once the slips are about four inches long, I break them off the tuber and put them in a jar of water. They root in a few days. I only sprouted a couple of tubers for fun, but now I wish I had started more. For some reason, I haven’t been able to find slips in local garden centers yet this year.

The Propagator is the host of Six on Saturday.  Head over there to see his Six for this week and find links to the blogs of other participants.

Paphiopedilum Johanna Burkhardt

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I have previously written about two fine old primary hybrids made with Paphiopedilum rothschildianum: the Victorian P. Lady Isobel and P. Saint Swithin. Here is a modern one, and it may well be the best.

Paphiopedilum Johanna Burkhardt is P. rothschildianum x P. adductum, and it was registered in 1994. My plant was made using P. adductum var. anitum as the pollen parent, and the results are spectacular. P. rothschildianum has contributed flower size, number, and overall form, while genes from the very dark P. adductum var. anitum have produced a dorsal sepal, petals, and pouch with dark reddish-brown markings on a yellow background. P. adductum var. anitum has also reduced the overall size of the plant, without affecting flower size; this plant has about half the leaf-span of my other P. rothschildianum hybrids, but its flowers are just as large, if not larger. A Google search for this grex will turn up pictures of other clones, many of them awarded, with huge, muscular-looking flowers and dorsal sepals that are almost black.

P. adductum var. anitum is sometimes considered a separate species, P. anitum, in which case this hybrid would be P. Wössner Black Wings (P. rothschildianum x P. anitum). From a horticultural point of view, there’s something to be said for distinguishing the dark plants made with P. adductum var anitum from those made with lighter colored P. adductum clones. However, the International Orchid Register lists P. Wössner Black Wings as a later synonym of P. Johanna Burkhardt, and both the Kew World Checklist of Selected Plant Families and a recent checklist of the genus Paphiopedilum (Koopowitz, H., 2018, Orchid Digest 82: 178-235) consider P. anitum to be a synonym of P. adductum.

Eight hybrids using P. Johanna Burkhardt as a parent have been registered, but none of the photos I have seen suggest that they are any better than–or even as good as–their parent. I’d go so far as to say that in this group of orchids, the primary hybrids are almost always better than complex hybrids. After more than 120 years, P. Lady Isobel and P. Saint Swithin are still well worth growing, and I suspect that the same will be true of P. Johanna Burkhardt in another century.

Paintbrush lily

Inflorescence of Scadoxus puniceus

This is exciting! After about six years in the ground, my Scadoxus puniceus has finally decided to flower. I was afraid that I wouldn’t get it to see it in full bloom: The day after I noticed a bud emerging from the mulch, the temperature dropped to 28 F (-2.2 C), so I surrounded it with bubble-wrap and covered it with a large plastic pot. That seemed to be sufficient insulation, because a couple of weeks later I have this beautiful orange inflorescence. The many small flowers are surrounded by petal-like spathes, giving it the appearance of a large single bloom.

Scadoxus puniceus is an African member of the Amaryllidaceae, the daffodil family, so it is not a true lily. Its range in the wild extends from Western Cape Province in South Africa northwards to Tanzania, with disjunct populations in Ethiopia [1}. Given its tropical and subtropical native habitat, it is somewhat surprising that it has done so well in my garden. It has survived temperatures as low as 5.5 F (-14.7 C) when buried under a thick layer of mulch, and despite its reported preference for a dry winter dormancy, it grows in clay that stays wet all winter long.

I suspect it took so long to flower because it is heavily shaded in summer by a large American beautyberry bush (Callicarpa americana). Last year, I planted a couple of young plants in sunnier spots. They survived the winter but are still too small to flower. Maybe next year.

Reference

1. Duncan, G., Jeppe, B., and Voight, L. (2016)  The Amaryllidaceae of Southern Africa, Umdaus Press, Pretoria, South Africa.

A lichen mimic

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I found this beautiful caterpillar crossing a path on Thursday. It’s the larva of the ilia underwing moth (Catocala ilia), and it would be well camouflaged on patches of lichen that sometimes decorate the bark of the oak trees on which it feeds. Supposedly, the caterpillars of C. ilia come in two color forms, this lichen-mimic form and a second form that is mottled brown to match the bark of oak trees. However, the only pictures I can find online are of the lichen mimic, probably because it looks cool.