First bloom: Hippeastrum calyptratum

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Hippeastrum calyptratum

It’s frigid outside, but with a little help from LP gas (OK, a lot of help), it’s the tropics in my greenhouse.  This week, the star is a seed-grown Hippeastrum calyptratum bulb, flowering for the first time four years after germination.

H. calyptratum is a very unusual amaryllid from the Atlantic Forest of southern Brazil, where it grows as an epiphyte on tree trunks. The pale green flowers are pollinated by bats and are often reported to produce a odor like burning plastic.  To my nose, they smell more like wet paint, but the fragrance is not very strong–at least not from this seedling.

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There are two (possibly three) other epiphytic Hippeastrum species.  I previously posted on H. aulicum when my plants bloomed in autumn.  The third epiphytic species, H. papilio is currently blooming a few feet away from the H. calyptratum, and a different clone bloomed earlier, at the same time as my H. aulicum.

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Hippeastrum papilio

The fourth epiphyte, H. arboricola, is rather mysterious.  It was apparently described from a single plant found growing on a fallen tree in a clear-cut forest and has not been seen since.  It is not clear if H. arboricola represents a distinct epiphytic species, possibly now extinct, or if it was a terrestrial species that was growing opportunistically on a tree.

H. aulicum and H. papilio are large, robust plants, very easy to grow in a mix of commercial potting soil and permatill (stalite).  When I tried that mix with H. calyptratum, the plants did well initially but later lost their roots.  In some cases, the entire basal plate rotted, destroying the bulb.  I now use a very open, wholly inorganic mix of scoria (red lava rock) and permatill in terracotta pots and have much better results. As befits an epiphyte, I plant the bulb high in the pot, with just a few large chunks of scoria holding it in place.  The roots are quite happy to wander around on the surface of the mix.

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Hippeastrum calyptratum (left) and Hippeastrum papilio (right)

Assuming that my blooming plant is close to full size, the bulbs of H. calyptratum seem to be significantly smaller than those of H. aulicum and H. papilio, and the leaves are proportionally shorter and narrower.   H. calyptratum shares with its larger epiphytic cousins a growth cycle that is quite different than that of the Hippeastrum (“Amaryllis”) hybrids sold for forcing in winter.  H. calyptratum has a short dormancy in mid-summer, but it retains some of its leaves and does not want to be bone dry for long periods while dormant.  As temperatures cool in autumn, my plants begin growing again, and they continue producing new leaves intermittently through the winter.

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Colonists

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Recently, I was walking along Morgan Creek in Chapel Hill, not far from the North Carolina Botanical Garden, when I noticed what I took to be an unusually extensive and dense population of Hexastylis arifolia, the little brown jug.

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Closer inspection revealed that the plants were actually Cyclamen hederifolium, a native of Mediterranean Europe.  The plants were growing on a steep hillside, where rocks and loose soil have slowly slid down the slope.  A few plants extended onto the wetter, more compacted soil of the flood plain, but that was clearly not their favored habitat.

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Nearby were a few plants of the real Hexastylis arifolia.

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Hexastylis arifolia (little brown jugs)

These Cyclamen hederifolium plants had clearly escaped from cultivation, but I don’t think they can really be considered invasive.  The true invasives are plants that form dense stands, choking out native species–things like Eleagnus species,  Ligustrum sinense (Chinese privet), Hedera helix (English Ivy), Pueraria montana (Kudzu), and Microstegium vimineum (Japanese stiltgrass).

Cyclamen seeds are distributed by ants, so the plants are unlikely to spread as far as those species with windborne seeds or berries that are eaten by birds.  The relatively sparse and low-growing leaves of C. hederifolium are also unlikely to smother other woodland plants–not that there is much else that likes to grow in the dry, unstable soil that the cyclamens seem to favor.

Not far from the cyclamens, I did see several other species with more potential to be invasive. Mahonia bealei (leatherleaf mahonia) and Ilex cornuta (Chinese holly) were naturalized in the woods, and of course, English ivy is ubiquitous.  The beautiful variegated leaves of Arum italicum stood out in the wet soil near the creek.  I had been thinking of adding A. italicum to my garden, but given its ability to spread and potential to be invasive in the mid-Atlantic region, I’m now not sure that’s a good idea.

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Arum italicum (lords-and-ladies) growing beside Morgan Creek

Although the C. hederifolium are probably no threat to native ecosystems, seeing them in an ostensibly wild area was a good reminder that the plants we grow in our gardens may not always stay there.

Eucrosia mirabilis

A couple of horticultural rules of thumb:

1. If an orchid is named after the Rothschild family, it is sure to have spectacular flowers.  cf. Vanda Rothschildiana, Paphiopedilum rothschildianum, Eurychone rothschildiana, Bulbophyllum rothschildianum.

2.  If a plant’s species epithet is some variation on “mirabilis” or “mirabile,” it is probably something special.  After all, “mirabilis” means wondrous, amazing.

Eucrosia mirabilis, blooming now in my greenhouse, lives up to its name.

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Eucrosia mirabilis inflorescence

E. mirabilis is a member of the Amaryllidaceae from South America.  Its sepals and petals are fairly small and a dull yellowish green color, and if that’s all there was to the flowers, it wouldn’t be worth growing.  But as you can see, the extremely elongated stamens and pistil are what make the flower amazing.  All of the flowers on an inflorescence open at the same time, giving the appearance of a large mop or head with long white hair.  The effect is very dramatic.

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Flowers just starting to open.  The folded stamens and pistil emerge limp and wrinkled, and slowly expand over several days.

The May 1, 2006 issue Curtis’s Botanical Magazine gives a good description of the ecology of E. mirabilis and its history in cultivation [1].  The species was described 1869 with notes indicating that it was from Peru, and it seems to have remained in cultivation until the 1870s–there is an herbarium record at Kew from 1876.  It was then lost for more than 100 years, and in 1997 was declared extinct by IUCN.  Surprisingly, researchers in Ecuador (not Peru) rediscovered the species in the same year that it was declared extinct, and seed, probably originating from Ecuadorian plants, entered cultivation in the late 1990s.

In nature, E. mirabilis grows on rocky hillsides among Opuntia cactus (prickly pear), so it needs bright light and very well drained soil.  I attempt to replicate this habitat by growing the bulb in an 8″ diameter terracotta pot with a well-drained mix of sand, permatill, and a little commercial potting soil.  During the spring and summer, I grow it outdoors in full sun, and it produces a pair of large, paddle-shaped leaves.  When the leaves start to wither in early autumn, I move it into the greenhouse for several months of warm, dry dormancy.  My plant always flowers in December or January, consistent the bloominng season in the wild, but plants in England are reported to bloom in April and May [1].  It is completely leafless while flowering, and the long inflorescence emerging from an apparently empty pot adds to the bizarre appearance.

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My bulb has shown no inclination to form offsets, so I suspect it must be propagated by seed.  Luckily, the plant is self fertile, and I have several second generation seedlings coming along.  I have donated extra seed to the Pacific Bulb Society seed exchange,  and I’ll probably be sending more to the SX in a couple of months.

Reference

Matthew, B. and Lewis, G. (2006).  557. Eucrosia mirabilis (Amaryllidaceae).  Curtis’s Botanical Magazine 23:157-164.

Massonia depressa

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Flowers of Massonia depressa

What types of animals do plants employ as pollinators?  There are insects, of course:  bees, wasps, butterflies, moths, flies of all kinds, even beetles.  There are hummingbirds in the new world and sunbirds in the old.  Some tropical flowers are pollinated by bats.

You can often deduce the natural pollinator of a flower by paying attention to its shape, color, and fragrance.  Moth-pollinated flowers are white or green, often with long nectar spurs, and tend to be fragrant at night.  Butterfly-pollinated flowers are roughly the same shape but brightly colored.  Bird-pollinated flowers are tubular or bell-shaped, usually red or orange, and are generally scentless because birds depend on sight more than smell.  Fly-pollinated flowers often smell like carrion or feces and may look like it too.

So, what pollinates the flowers shown above?  They’re a dull brown, filled with thick, gelatinous nectar, have an odd yeasty smell, and sit on the ground.

Give up?  Gerbils.

This is a gerbil-pollinated flower.

Gerbils.

Massonia depressa grows in the arid Karoo region of South Africa.  It is a winter-growing bulb that produces a single pair of large, fleshy leaves that grow flat on the ground.  A study of plants growing in the wild [1] showed that the flowers attracted several species of rodents, including two species of gerbils and three species of mice.  At least some of the mice ate the M. depressa flowers, but the gerbils fed exclusively on the nectar, never damaging the flowers but getting their snouts coated with pollen in the process.

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Massonia depressa leaves and bud

M. depressa certainly isn’t the most beautiful species in the hyacinth family (Hyacinthaceae), but it is fun to grow as an oddity.  My plant spends its summer dormancy in the greenhouse, bone dry from March until September.  In late September, I put the pot outside and start watering.  The plant stays outdoors until the first frost is forecast, whereupon I put it back in the greenhouse.  It would probably tolerate some frost if growing in the ground, but I don’t want to risk the pot freezing.  Back in the greenhouse, it usually flowers at the beginning of December.  It is currently blooming on schedule.

Reference

Johnson, S.D., Pauw, A., Midgley, J. (2001) Rodent pollination in the African lily Massonia depressa (Hyacinthaceae).  American Journal of Botany 88:1768-1773.

Book Review: The Amaryllidaceae of Southern Africa

This book review was also published in the most recent issue of The Bulb Garden, the newsletter of the Pacific Bulb Society.

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Graham Duncan, Barbara Jepp, and Leigh Voigt (2017). The Amaryllidaceae of Southern Africa, Umdaus Press, Pretoria, South Africa.

When I first learned of the impending publication of The Amaryllidaceae of Southern Africa, I wondered whether it would be worth purchasing.  After all, a huge amount of information on South African amaryllids is already available without cost at web sites like the PBS wiki or PlantZAfrica.com, a site maintained by the South African National Biodiversity Institute.  However, early descriptions of the book were uniformly positive, and I have hesitated before to purchase an attractive horticulture book, only to discover that its limited print run has sold out and second hand copies are far beyond my budget.  Thus, when the book finally became available, I searched around for the best price and ordered a copy from a distributor in the United Kingdom.  I was not disappointed.

Considered first as a physical artifact, the book is an impressive specimen.  It is printed on heavy, glossy paper bound together with a satin ribbon bookmark.  The endpapers and tough dust jacket are beautifully decorated with line drawings of amaryllid inflorescences and the dust jacket also has a lovely color illustration of Brunsvigia radulosa.  Weighing nearly three kilograms, the book is almost too heavy to read comfortably unless it is placed on a table, and it would certainly not be a good field guide.  However, its physical presence gives the impression that it will outlive the purchaser.

And the content?  This is the finest botany/horticulture book I have read in a long time.  As most advertisements and descriptions indicate, the book’s main selling point is its botanical illustrations, which represent almost forty-five years of work by Barbara Jeppe and her daughter Leigh Voigt.  The book covers every single species in all of the amaryllid genera found in Southern Africa, a region encompassing both the summer- and winter-rainfall regions of South Africa, Swaziland, Lesotho, Namibia, and Botswana.  Each full-color botanical illustration shows the bulb, foliage, flowers, and fruit.  A notation at the bottom of each illustration indicates its scale as a percentage of life-size, making it easy to determine the actual size of the flowers.  In my browsing of the book, I found only a couple of species illustrated with older paintings or lacking an illustration, because no living material was available to the artists.

All species, including those few with no illustration, have a detailed description written by Graham Duncan, the curator of the indigenous bulb collection at Kirstenbosch National Botanical Garden in Cape Town, South Africa.  In addition to a physical description, Duncan’s text includes a brief history of the species (including provenance of the illustrated plant), flowering period, distribution and habitat, conservation status, and cultivation notes.  This latter section will probably be of great interest to bulb enthusiasts and gardeners.  If, like me, you sometimes have trouble remembering which parts of South Africa receive winter rainfall and which months in the southern hemisphere correspond to our northern hemisphere growing season, you’ll be pleased to see that the cultivation instructions usually state exactly when a species should be watered in terms of season, not months of the year.

The various genera and species are presented in alphabetical order, making it easy to find a species of interest.  Each genus is introduced with a more general description that includes numerous color photographs, many of them showing plants in habitat. Introductory material at the front of the book includes sections on amaryllid biogeography and survival strategies.  These sections were particularly interesting to me, because I find that much of the fun of growing exotic plants lies in learning about their biology, evolution, and habitat.

The end of the book includes a key to all genera and species, a glossary, and a more detailed cultivation guide split into sections for growers in the northern and southern hemispheres.  The northern hemisphere guide includes helpful instructions for acclimatizing bulbs imported from South Africa, as well as lists of recommended species for cultivation outside.  These lists are, I think, the least useful aspect of the book for growers in North America.  The cultivation guide was clearly written with the United Kingdom in mind, and there is no obvious way to translate the “hardy” and “half-hardy” categories into USDA climate zones.  In some cases, the cultivation guide seems too conservative, stating that Nerine bowdenii is “the only fully hardy summer-rainfall amaryllid” and that Crinum bulbispermum is merely “frost-hardy.”  With these minor quibbles, though, I am still impressed by the cultivation guide and think that its information on propagation, pests and diseases, and potting media will be of great utility to North American growers.

For me, the biggest surprise in this book has been learning just how many absolutely gorgeous amaryllids there are that do not seem to be in cultivation in the United States.  Perhaps the list of seed and bulb suppliers at the end of the book will offer me the opportunity to test those instructions for acclimatizing imports.