Six on Saturday #59 (August 1, 2020)

This week’s Six on Saturday includes a couple of native species, an unusual vegetable, a cute little bulb from South Africa, a classic Victorian hybrid, and a greenhouse orchid that is really very nasty.

1. Bulbophyllum phalaenopsis

Bulbophyllum-phalaenopsis

This is not an orchid for growing on your windowsill or decorating your table at a dinner party.  If you think that the flowers of Bulbophyllum phalaenopsis look a bit like rotting meat covered with yellowish maggots, I can assure you that they smell exactly the way they look.  B. phalaenopsis is pollinated by flies looking for a place to lay their eggs, but if the fly is fooled by the ersatz carrion, the maggots will starve.

2. Canna ‘Ehemannii’

canna-ehemannii

C. ‘Ehemannii’ is an old Victorian hybrid of C. iridiflora crossed with (probably) C. indica, and it has inherited its drooping inflorescence from C. iridiflora.  Several modern C. iridiflora hybrids, including Canna ‘Orange Crush’ failed to survive the winter in my garden, but this plant, which I received from Bittster of Sorta Like Suburbia fame, has survived two winters so far.  I’m glad, because I adore the intense magenta color that is so very different than any other canna in my garden.

3. Sabatia species

Sabatia

This pretty little native wildflower often shows up at the edge of my lawn (i.e. the patch of weeds and moss that survive being mowed).  I think it is Sabatia angularis (rosepink), a widespread annual, but I am not certain.

4. Eucomis vandermerwei

Eucomis-vandermerwei

E. vandermerwei, from South Africa, is one of the smallest of the pineapple lilies. Along with E. zambesiaca, it seems to be resistant to the wilting exhibited by many other Eucomis in hot sunlight, making it a good choice for a North Carolina garden.

5. Allium cernuum (nodding onion)

Allium-cernuum

The nodding onion has a very wide native range, spanning the United States from Atlantic to Pacific.  In North Carolina its distribution is spotty, and although it has been reported from this county, my plants were purchased from the North Carolina Botanical Garden.  Leaves and flowers are edible but strong tasting.  I prefer to eat garlic chives.

6. Melothria scabra (Mexican sour gherkin, cucamelon)

Melothria_scabra

First fruit from from a plant that we bought on a whim from a veggie seedling rack this spring.  The plant looks almost identical to the weedy Melothria pendula but its fruit are better tasting.  I could probably have left these to get a bit bigger, but then I’d risk losing them to the tree rats.

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

Lady Hooker and Mr. Stone

Paph_hookerae1
Paphiopedilum hookerae

Currently blooming in my greenhouse: two slipper orchids from Borneo whose specific epithets are closely tied to the world of Victorian botany and horticulture.

Paph_hookerae2
P. hookerae foliage

Paphiopedilum hookerae is noted for the striking beauty of its tessellated foliage and extremely long inflorescence bearing a single glossy flower in rich purple and cool green. Scientific names that end in “ae” often commemorate women, and in this case the woman was Maria Hooker (née Turner).  As far as I can tell, Lady Hooker was not noted for direct botanical contributions, but she was the daughter, wife, and mother of botanists.  Her husband, Sir William Jackson Hooker was Director of the Royal Botanic Gardens, Kew from 1841 until his death in 1865, two years after P. hookerae was described.  Her son, Sir Joseph Dalton Hooker, was a close friend of Charles Darwin.  He served on HMS Erebus during the Ross expedition to Antarctica, collected plants in the Himalayas and western United States, and succeeded his father as Director of RBG Kew in 1865.

Paph_stonei
Paphiopedilum stonei.  Sadly, by the time the third bud finished opening, these flowers had been disfigured by an infestation of aphids

Paphiopedilum stonei is a much larger species than P. hookerae.  It has unmarked leaves that can be up to 2 feet long, and an inflorescence bearing 3-5 large flowers with strap-like petals.  P. stonei is notoriously slow-growing and it is one of the Paphiopedilum species that never seem to show their best in photographs.  In life, the flowers are impressive and elegant, while in pictures they often appear awkward and a little grotesque.

P. stonei was described by William Jackson Hooker, and he named it in honor of a gardener–but not just any gardener.  Robert Stone was the gardener who maintained the collection of John Day, an orchid enthusiast most famous for his thousands of paintings illustrating orchid species.  John Day owned the first plants of P. stonei imported into England, and those plants, cared for by Robert Stone, served as the basis for the species description published by Hooker in 1862.

In addition to its own considerable horticultural merits, P. stonei is noteworthy as a parent of the beautiful hybrid Paphiopedilum Lady Isobel, whose name and history I have previously discussed.

Renanthera Jenny Wren

Renanthera_Jenny-Wren

‘Tis the season for Renanthera flowers.  My R. imschootiana is still blooming, and this week the buds on my R. Jenny Wren started to open.  Renanthera Jenny Wren is a complex hybrid whose ancestry incorporates R. storiei, R. philippinensis, R. monachica, and R. imschootiana.   The mix of lowland (R. philippinensis, R. monachica) and higher elevation species (R. imschootiana, R. storiei) has produced a fairly adaptable grex.  Although it has several doses of genes from the giant R. storiei, the other parent species are smaller, resulting in a more manageable plant. Flowers seem to be somewhat variable.  My plant has rich, red flowers with darker red spots, but here is a plant with red spots on an orange background, more reminiscent of R. monachica.

The cross was made by Carter and Holmes Orchids, but I requested, and was granted, permission to register the grex when I first bloomed it in 2004. I named it for my wife, Jennifer.

Renanthera imschootiana

Ren_imschootiana1

Depending on how I do the math, I have been waiting to see these flowers for eight years, or just over twenty five years.  Back in the mid 1990s, when I first started growing orchids, I purchased a seedling of Renanthera imschootiana ‘Saigon’ x self to grow under fluorescent lights in my student apartment in Michigan.  Orchid growers will recognize that it was a poor choice for my growing area; Renanthera species and hybrids require high humidity and very bright light–up to full tropical sun.  After a few years, I came to the same realization and sold the plant to make room for something I had a chance of flowering.

Fast forward to about 2005.  I now lived in North Carolina and had a greenhouse where I could give large orchids much brighter light and higher humidity.  I still loved red flowers, and the very rare R. imschootiana has a certain mystique. I decided to try growing the species again

But I couldn’t find a plant to buy.  This isn’t uncommon if you go searching for one particular orchid.  There are about 28,000 orchid species and hundreds of thousands of registered hybrids, so only a tiny fraction are in commercial production at any time.  Someone flasks a batch of seedlings, and that species is available for sale until they run out.  Then, the species may be virtually unobtainable, unless you know a grower who will give you a division, until someone else produces a new batch of seedlings.

Finally, in 2012, I purchased a seedling of R. imschootiana ‘Newberry’ x ‘Saigon’ from Carter and Holmes Orchids.  That one of the parents of the new seedling was the same as the parent of my old seedling probably speaks to the small gene pool of cultivated plants in the U.S. (Carter and Holmes doesn’t seem to have plants for sale any more, but I see that seedlings are available from Santa Barbara Orchid Estate).

So, about the plant:  R. imschootiana is a relatively small species in terms of leaf-span, although it can grow tall with time.  It is basically a slow-motion vine, taking ten years to grow the distance that a honeysuckle vine could grow in a week, but it eventually grows long enough to need support.  The main stem occasionally branches, and the roots and inflorescences grow from leaf axils at random intervals.  My plant is potted in a 4″ terracotta pot filled with large chunks of scoria (red lava rock).  When it got top heavy, I put the 4″ pot in a 6″ pot, and roots have filled the space between the pots.  The vining stems are supported by several stiff wires.

Ren_imschootiana3

After a few years in my greenhouse, the plant sprouted a stem that resembled an inflorescence, but instead of flowers it produced a single terminal keiki (plantlet).  The next year, the same thing happened, and the year after.  Many of the Renanthera species and hybrids more common in cultivation are lowland tropicals that grow well in a warm greenhouse, but R. imschootiana is from higher elevation (Assam, northern Indochina, Yunnan) and is noted for tolerating winter temperatures near freezing. Suspecting that the plant was too comfortable with a minimum temperature of 60 F in my greenhouse, I left it outside during the autumn of 2018 until temperatures dropped to near freezing.  I then put the plant on the floor of the greenhouse near the door and reduced watering so that it stayed cool and dry for much of the winter.  Whenever the weather was dry and above freezing, I put it back outside again.  Result: nothing.  Last winter, I just left the plant on a bench in a sunny part of the greenhouse and watered it along with all the other orchids.  Result:  four inflorescences.

So, ~1995-2020 = 25 years.  2012-2020 = 8 years.  Either span is a long time to wait.  I just wish I knew what induced the plant to flower this year.

Ren_imschootiana2

Spring lady’s slippers (Six on Saturday #55, May 9, 2020)

The weather has turned unseasonably cold, to the point that the National Weather Service has issued a freeze warning for most of central North Carolina tonight.  If it does freeze, this will be the latest frost in more than 20 years, a full month after the average last freeze for this area.  Consequently, the tropical plants that I have been moving outside over the past few weeks will need to be moved back into the greenhouse or living room this afternoon, probably to stay there until Wednesday at least.  There’s not much to be done about subtropical plants out in the garden which are already well into their spring growth; hopefully the fresh canopy of deciduous leaves on the trees will provide some protection from radiative cooling.

For this week’s Six on Saturday, I am focusing on a single group of greenhouse plants:  tropical lady’s slipper orchids of genus Paphiopedilum.  A google search will turn up reams of information on cultivating paphs, so I’ll only say that I use a potting mix of Orchiata bark, large perlite, and stalite in roughly equal proportions.  To this mix, which is suitable for a wide range of orchids, I add a small amount of crushed oyster shell to provide calcium for the paphs that grow on limestone.

Although different species and hybrids flower throughout the year, there is a peak of blooming in spring.  Here are six that are flowering now.

1. Paphiopedilum philippinense varieties.

Paph philippinense-1

No prize for guessing the home range of this species.  P. philippinense is fairly widespread in the Philippine archipelago and consequently exhibits significant morphological diversity.  The plant on the left is a dwarf specimen that I have been growing since 1997.  Its relatively short petals would probably define it as P. philippinense var. laevigatum, a variety that is relatively uncommon in cultivation.  The taller plant, with its long twisted petals, fits the description of P. philippinense var. roebelenii and is more typical of the specimens that are favored by orchid growers.

Paph philippinense-2

2. Paphiopedilum QF Ikaika

Paph_hybrid

This is a new hybrid registered in 2019.  Its parentage is Paphiopedilum (rothschildianum x anitum) x philippinense, and I’m going to rate it a solid meh.  I assume the breeder was going for large size (from P. rothschildianum), dark color (from P. anitum), and twisted petals (from P. philippinense).  Instead, the plant inherited mediocre color, moderate size, petals with hardly any twist, and a small, squat pouch.  I’ll give it a few more years to mature, but if it doesn’t improve, it is destined for an orchid society raffle table.

3. Paphiopedilum venustum

Paph_venustum

According to Hennessy and Hedge [1], this species from the southeastern foothills of the Himalayas was the first tropical lady’s slipper introduced into cultivation (collected 1816, flowered in England 1819).  It has been popular ever since for its veined pouch and distinctively mottled foliage.  It definitely comes down on the bizarre/grotesque end of the scale, rather than pretty/elegant.  I like it.

4. Paphiopedilum callosum var. sublaeve

Paph_callosum-sublaeve

A dwarf variety of P callosum that seems to be somewhat intermediate between that species and P. barbatum.  This is a first-bloom seedling that I got as a free bonus in an orchid order about a year ago.

5. Paphiopedilum lowii

Paph_lowii2

Compared to the P. lowii that I blogged about last year, this clone has a darker pouch, more brown pigment in the dorsal sepal, and more horizontal petals.  I particularly like the horizontal stance of the petals–

6. Paphiopedilum appletonianum with deformed flowers

Paph_appletonianum

This is the second time this plant has bloomed, and the flowers were deformed last year, too.  I’ll give it one more chance to produce a normal flower before I toss it in the compost bin.

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

Reference:

1. Hennessy, E.F. and Hedge, T.A. (1989) The Slipper Orchids, Acorn Books, Randburg, R.S.A.