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.

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Six on Saturday #18, December 9, 2017: books for piedmont gardeners

sleet
Yuck.

For the past twenty four hours, we have had more or less constant rain and sleet with temperatures hovering right around freezing.  The ground is warm, so we don’t have much accumulation.  But the weather doesn’t make me want to go outside, not even to the greenhouse.  This is a day for lighting the wood stove, drinking tea, and reading.

Reading.  If I write about gardening books, I won’t have to go outside.  So, for my first “Six on Saturday, Library Edition,” here are six books that I think will be of interest to gardeners in the NC piedmont (and, perhaps, further afield).

1. Elizabeth Lawrence (1991). A Southern Garden,  University of North Carolina Press, Chapel Hill and London.

southern-garden

A Southern Garden was originally published in 1942 and has remained a favorite of North Carolina gardeners ever since.  Elizabeth Lawrence structures her book around the four seasons, describing the bulbs, perennials, and shrubs blooming throughout the year in her Raleigh garden.  The book is an eloquent description of the joys of gardening in the south, and its advice is still valid.  At the end of the book are exhaustive tables indicating earliest and latest date of first bloom and length of blooming season collated from notebooks kept by Elizabeth Lawrence and her mother.  The index of my 1991 reprint includes updated botanical nomenclature, as well as the names originally used by the author.

2. Nancy Goodwin, with illustrations by Ippy Patterson (2005).  Montrose: Life in a Garden, Duke University Press, Durham and London. 

Montrose

This book can be viewed as an updated successor to A Southern Garden.  As indicated by the title, it is a month by month account of life in Montrose, Nancy Goodwin’s garden in Hillsborough, North Carolina.  Descriptions of plants and animals are interspersed with anecdotes from the Goodwins’ life and beautiful black-and-white or color illustrations by Ippy Patterson.

3.  Scott Ogden (2007).  Garden Bulbs for the South, Timber Press, Portland.

bulbs-south

Many books on bulbs focus on plants suitable for northern Europe, or the northeast and northwest United States.  It is great to find a book covering those bulbs that grow well in the southeast and return year after year.  In addition to describing heat-tolerant varieties of old favorites like daffodils and tulips, Ogden provides welcome information on southern specialties like Crinum, Lycoris, Hymenocallis, and ornamental gingers.

4.  Albert E. Radford, Harry E. Ahles, C. Ritchie Bell (1964, 1968).  Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill.

books

This massive tome (1183 pages) is invaluable for identifying wild flowers and garden weeds or for determining if native plants offered by nurseries are really native or just “native.”  Each genus has a key of native and introduced species, and the range maps show distribution in North and South Carolina at the level of counties.  My main problem with this book is the same issue I used to have with encyclopedias (for the youngsters, those were like wikipedia printed out on paper and bound in multiple volumes).  When paging through to find a plant that I have identified in the index, I am often so distracted by other plants that I forget which page I was looking for.  It sometimes takes be three or four returns to the index before I actually get to the plant I originally wanted to read about.

5.  William Chambers Coker and Henry Roland Totten (1945).  Trees of the Southeasten States, University of North Carolina Press, Chapel Hill.

Trees

Although smaller than Vascular Flora of the Carolinas, this book is just as distracting when I am searching backwards from the index.  I found this 1945 second edition (first edition, 1934) in an old bookshop in Charleston, South Carolina.  My copy came with an inscription from “As You Like It” written by the original gift-giver, and old dried leaves, presumably inserted by the gift recipient.  The authors were professors of botany at the University of North Carolina, and the scientific summaries are leavened with delightful descriptions of individual trees they knew and loved.  Many of those trees have been replaced by houses and shopping centers, but some, particularly those on the UNC campus, can still be seen.

6.  Bernard S. Martof, Wlliam M. Palmer, Joseph R. Bailey, Julian R. Harrison III, photographs by Jack Dermid (1980).  Amphibians and Reptiles of the Carolinas and Virginia.  University of North Carolina Press, Chapel Hill.

amphibians-reptiles

Gardens aren’t just about plants. Hopefully, we are also creating habitat for native wildlife.  To identify the creatures sharing your garden, you could use the Peterson’s field guide covering the eastern U.S. or the Audobon Society Guide covering all of North America, but this book focusing on three states has much more relevant detail and more useful range maps.  I like to use the margins for notes indicating when I see a particular species for the first time.

That’s my six for this week.  For more Six on Saturday posted by gardeners who might actually have gone outside, head over to the Propagator for the proprietor’s Six and links to other blogs.

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.

Rubiaceous Ant Plants (Six on Saturday #17, November 25, 2017)

After a couple of weeks absence, here’s another Six on Saturday.  As with previous posts on Pachypodium and Nepenthes, I’m focusing on a single group of greenhouse plants this week.

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Myrmecodia platytyrea (Mossman Gorge form) overflowing a 5-inch pot

The epiphytic myrmecophytes (ant plants) of the coffee family, Rubiaceae, are surely some of the strangest plants that grow anywhere in the world.  Their overall appearance is often grotesque: gray or silver or brown blobs with thick, armored stems and sharp spines derived from modified roots.  They cling to tree trunks or hang upside down below horizontal branches, looking like aliens that have inexplicably settled in an Asian forest.  And to top all of that, their real strangeness is hidden inside.  Soon after a seedling ant plant germinates, the hypocotyl–the stem below the cotyledons–starts to swell into a tuber.  As the plant grows, tissue within the tuber dies in a genetically programmed manner, first forming a hollow space and then expanding into a series of tunnels and chambers.  The tunnels are connected to the outside by entrance holes around the base of the tuber, and the chambers are often aerated by pores.

All of this baroque development is for the benefit of symbiotic ant colonies who set up housekeeping in the artificial nest that the plant has grown.  Both insects and plant benefit from the relationship.  The ants get a secure home, and the plant is fed by the ants.  The ants live in smooth-walled chambers and deposit leftover fragments of insect prey and other waste in chambers with wart-like excrescences on the walls.  As the waste decomposes, the plant absorbs nitrogen through the warts.

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Myrmecodia tuberosa cut to reveal interior chambers (a photo from my defunct ant plant website, ca. 1998)

 

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Closeup of chambers.  Arrows indicate two warted chambers.  Smooth chambers can be seen at the center of the slice.

The natural range of the rubiaceous ant plants extends from Thailand to Australia and east as far as Fiji, but the greatest diversity is found on New Guinea.  In the mid-1990s, when I first became interested in ant plants, only about five species were in cultivation, and they were very hard to find.  With some effort (i.e. obsessive searching), I managed to connect with a few other like-minded growers via email and traded seed and seedlings with the curators of several botanical gardens.  These days, the plants are (somewhat) easier to obtain, and a wider range of genera and species are in cultivation thanks to the efforts of a handful of hobbyists and nursery owners from around the world.  Several nurseries in Europe and the U.S.A. sell seedlings, and plants are occasionally available on eBay.

So without further ado, here are six (on Saturday) ant plant species:

1.  Myrmecodia platytyrea (Mossman Gorge form)

The plant shown at the top of this post is a very vigorous Myrmecodia descended from material originally collected in northern Queensland.  Like most of the rubiaceous ant plants in cultivation, M. platytyrea has flowers that self-pollinate, so seedlings remain true to type over multiple generations.  The Mossman Gorge form of M. platytyrea produces long, sharp spines and very vigorous roots that often invade the pots of its neighbors.  Its leaves are narrower and more succulent than other cultivated M. platytyrea descended from plants collected in New Guinea.

platytyrea-mossman-stem

The shield-like leaf bases on the stems of M. platytyrea are called clypeoli.  The spines bordering the clypeoli hide alveoli, pits in which the small white flowers develop and from which the orange fruit protrudes when ripe.

2.  Myrmecodia sp. “Pink Fruit”

pink-fruit

This species has very strong sharp spines and pink fruit.  It is commonly cultivated by ant plant enthusiasts, but its origins are obscure.  Possibly, it is M. tuberosa ‘Papuana’ which grows in New Guinea and northern Australia.

3Myrmecodia tuberosa

tuberosa

tuberosa-stem

This is the most variable and widespread Myrmecodia species, with a range extending from Malaysia to Australia.  The form shown here does not have strongly developed clypeoli, so you can easily see the elongated alveoli filled with papery bracts.

4.  Myrmephytum beccarii

myrmephytum

Myrmephytum is a genus of five species found in the Philippines, Sulawesi, and western New Guinea.  M. beccarii is from the Philippines, and was introduced into cultivation in the U.S. around 2006.

5. Hydnophytum moseleyanum

moseleyanum

H. moseleyanum is a lowland species from New Guinea and Australia.  Hydnophytum species usually lack spines and have many elongated branches without clypeoli and alveoli.  Their chambers are less complex than those of Myrmecodia.  Note the large entrance hole on the side of this tuber.  Above and left of the entrance hole, a patch of papery dead tissue is peeling away to reveal a new hole.

6.  Hydnophytum formicarum

A very variable and widespread lowland species from Thailand, Malaysia, and Indonesia.  Several different forms varying in size and color are in cultivation.

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Hydnophytum formicarum.  A large form from Thailand with entrance holes generally restricted to the underside of the tuber.  The tuber is partially obscured by moss growing up its sides and is larger than it appears.  This plant is twenty-one years old and was the first ant plant I grew from seed.
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Hydnophytum cf. formicarum. A plant distinguished by its very broad leaves and smaller tuber with proportionally very large entrance holes.
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Hydnophytum cf. formicarum from Belum rainforest, peninsular Malaysia.  This is a dwarf form with brown, flattened tuber and tiny leaves barely as long as those of the Thai form are wide.  Notice the the small entrance hole on the right and pores on the lumpy region at left.

So, that’s six rubiaceous myrmecophytes.  For more Six on Saturday that is perhaps a little less botanically grotesque, head over to The Propagator.

Deciduous hollies

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Ilex ‘Sparkleberry’

“Holly” generally brings to mind evergreen species like English holly (Ilex aquifolium) or American holly (Ilex opaca) which are grown for their ornamental spiny foliage as much as for their red berries, but there are also deciduous species with soft leaves that are shed in autumn.  The best evergreen hollies are beautiful, stately trees, but for a punch of winter color, they can’t compete with the deciduous hollies whose heavy crop of berries are never hidden by leaves.

Two species of deciduous hollies are native to the piedmont, and I grow both of them in my garden, along with a commonly cultivated hybrid.  Their leaves are falling now, so they’ll be looking their best until hungry birds eat the berries in late winter.

Ilex verticillata (Winterberry)

Winter Red
Ilex verticillata ‘Winter Red’

I. verticillata thrives best in damp, acidic soil and full sun, but it will tolerate dry soil and part shade.  Dwarf clones of I. verticillata (e.g. ‘Red Sprite’) are great for small gardens, but since we have plenty of space, I planted the full-size ‘Winter Red’ and ‘Winter Gold.’  I. verticillata ‘Winter Red’ will approach 8 feet tall (~2.4 meters) and spread a similar distance with somewhat sprawling branches and root suckers.  Once they have their own roots, I have found that the suckers are easy to transplant, and removing some of them helps the shrub too look a little more tidy.

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Ilex verticillata ‘Winter Gold’

I. verticillata ‘Winter Gold’ apparently originated as a mutation of ‘Winter Red,’ so apart from the berry color, the two clones are almost identical. At first, I wasn’t very impressed with ‘Winter Gold,’ finding the color somewhat anemic, but over the years it has grown on me.  The golden berries of ‘Winter Gold’ look best in front of dark mulch, while those of ‘Winter Red’ are most dramatic against grass or snow.

All hollies are dioecious, with male and female flowers on separate plants.  Thus, to set berries on female plants like ‘Winter Red’ and ‘Winter Gold,’ you need a male plant that blooms at the same time.  For these late-blooming I. verticillata clones, the best pollinator is I. verticillata ‘Southern Gentleman.’  I have a single ‘Southern Gentleman’ tucked away at the edge of the woods, and it is sufficient to pollinate my three plants of ‘Winter Red’ and one ‘Winter Gold.’

Unfortunately, deer are very fond of the young twigs of I. verticillata which lack the spiky defenses of evergreen holly, and if the hoofed pests consistently nip off the new growth, you will end up with an awkwardly shaped bush and far fewer berries.  If you are in the piedmont and don’t garden behind a deer fence, you’ll need to frequently apply repellents.

Ilex decidua (Possumhaw)

As seen in the comparison picture below, the berries of I. decidua are significantly smaller than those of I. verticillata.  The I. decidua plants that I have seen in the wild have been upright shrubs, generally taller than wide, and the one in my garden has the same shape

I have not planted a male I. decidua, but my female plant sets a good crop of berries every year, probably after pollination by male I. opaca (American holly) trees that grow wild in the woods around our house.  I’m not sure if I. opaca pollen can produce fertile seeds on I. decidua, but I have never found any seedlings that appear to be hybrids.

 

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Comparison of deciduous holly berries:  (left to right) Ilex decidua, Ilex ‘Sparkleberry’, Ilex verticillata ‘Winter Red’, Ilex verticillata ‘Winter Gold’

Ilex ‘Sparkleberry’ (hybrid winterberry)

I. ‘Sparkleberry’ is a hybrid of I. verticillata and a Japanese deciduous holly, I. serrata.     After growing both ‘Sparkleberry’ and I. verticillata ‘Winter Red’ for about ten years, I don’t think the hybrid is an improvement over the native species.  ‘Sparkleberry has a slightly more upright and elegant appearance, but its berries are smaller than those of ‘Winter Red’ (see above), and they don’t tolerate very cold weather, becoming soft and discolored when those of ‘Winter Red’ are still perfect.

In my garden, I. ‘Sparkleberry’ blooms a week or two before late-blooming I. verticillata, so I can’t depend on it being pollinated efficiently by I. ‘Southern Gentleman’.  The best pollinator for I. ‘Sparkleberry’ is I. ‘Apollo,’ a male sibling from the same cross.  I have a single plant of ‘Apollo,’ which I forget about for most of the year, because it is such a nondescript shrub.

Conclusion:  Grow the native species.