Wintergreen orchids

The winter leaves of Tipularia discolor in our woods.  Notice the purple pigment on their undersides.

Winter is the best time to look for several orchid species that grow in the North Carolina piedmont.  You can wander through the woods without worrying about ticks, spider webs and poison ivy.  Just watch out for deer hunters.

1. Tipularia discolor (cranefly orchid)

T. discolor, a small colony of the typical spotted form

Tipularia discolor is one of the most common woodland wildflowers in our region.  They grow in almost every patch of woods, even where just a few trees have been left by developers.  The plants grow as scattered individuals or small colonies., and the drifting seed will also sprout in mulched flowerbeds that are shaded and dryish in summer.  T. discolor is very easy to find during the winter, when it bears a single leaf, and if you live almost anywhere in the piedmont, you could probably find a plant within a few minutes of stepping outside your front door.

They’re much more difficult to locate during the summer, because the foliage dies in spring and the midsummer flowers are small and dull.  The best way to find T. discolor flowers is to mark a colony in winter and return in July (hopefully avoiding the aforementioned ticks and spider webs).   You’ll be most likely to find flowers if you choose a colony that had the remains of inflorescences and dried seed capsules persisting in winter.  The flowers are pollinated by moths, and the column is twisted slightly to one side so that the pollen is deposited on the moth’s compound eye.

T. discolor flowers lurking behind our shed, July 26, 2017.

Although the classic “textbook” description of T. discolor says that the leaves have dark purple spots on their upper surface and purple undersides (see above image), I have found considerable variation in the plants growing in central North Carolina.  All of the following photos were taken in Orange County, NC, and I monitored the unusually colored forms for several years to be sure that their appearance wasn’t a temporary fluke.

No spots on upper surface.  This is the most common form growing on our property.

Metallic purple-green

Solid Purple.  I frequently see plants with leaves that emerge purple and fade to green, but rare clones like this plant retain the solid purple color all winter long.

White spots/variegation.  I have only seen this color in one colony.  The white spots were stable over several years.

2. Aplectrum hyemale (Adam and Eve, putty root orchid)

Aplectrum hyemale in Duke Forest

Aplectrum hyemale has a very similar growth habit, with a single leaf produced in autumn.  The leaves are slightly larger than those of T. discolor and are green with distinctive white stripes. We are near the southern edge of its range, and it is much less common than T. discolor.  I have only seen plants at two locations:  once in Duke Forest and once along the Eno River near downtown Hillsborough.

3.  Goodyera pubescens (downy rattlesnake plantain)

Goodyera pubescens in our woods

Goodyera pubescens is evergreen, not deciduous, but like T. discolor it is easier to find in the winter.  It grows in the same habitat as T. discolor but seems to be somewhat less common.  Its foliage is very beautiful, and various sources report that it has suffered from over-collection for gardens, terrariums, and flower arrangements.  For terrariums, at least, its tropical relatives are much better suited.  Just be sure to seek out artificially propagated plants.  Several G. pubescens seedlings have sprouted in the hardwood mulch that we spread on flower beds, so if you’re lucky that’s a possible way to obtain plants for your garden.

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Miracle Fruit

Synsepalum dulcificum (miracle fruit)

There’s not enough going on in the garden and greenhouse to support a “Six on Saturday” post today, but I think the first fruit on a strange little plant warrants a post all of its own.

Miracle fruit (Synsepalum dulcificum) is a nondescript little west African shrub with nondescript little white flowers.  Its name and its claim to fame come from the red berries which contain a unique glycoprotein called miraculin.  Miraculin binds to taste receptors that are responsible for detecting sweet substances and functions as a pH-dependent agonist [1].  In other words, miraculin can activate sweet taste receptors, but only under acidic conditions.  The result is that sour (acidic) substances temporarily taste sweet.

This sounded like a lot of fun to me, so about a year-and-a-half ago, I purchased a small. S. dulcificum plant to grow in the greenhouse.  After a rocky start when it got badly sunburned, the plant has recovered nicely and recently produced two berries.  My initial plan was to cut the berries in half so that all four family members could try them.  However, it turned out that the berries consist of a thin layer of white pulp sticking to a large central seed that resists subdivision.  In the end, my wife graciously chose to wait for the next crop (or maybe she wanted to use us as guinea pigs).  I chewed on a small fragment of skin and pulp shaved off the largest berry, and the kids had one berry each.

The skin/pulp was tart and fresh but didn’t have much in the way of a distinctive taste.  After chewing on the berries, the kids and I tried sucking on wedges of fresh lemon and sipping apple cider vinegar.  The results were exactly as described in the literature, but it was still startling to experience the effect ourselves. The lemons tasted like wonderfully sweet fresh lemonade.  The vinegar was great.  I could still smell the volatile acetic acid, but the taste was sweet apple juice.  The overall effect was a complex, spicy apple cider.

I see more buds forming on the plant, so hopefully we will soon have a larger crop of berries to experiment with.

Reference

[1] Koizumi, A., Tsuchiya, A., Kakajima, K.-I., Ito, K., Terada, T., Shimizu-Ibuka, A., Briand, L., Asakura, T., Misaka, T., and Abe, K. (2011).  Human sweet taste receptor mediates acid-induced sweetness of miraculin.  Proc. Natl. Acad. Sci. USA 108: 16819-16824.

Colonists

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.

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.

Nearby were a few plants of the real Hexastylis arifolia.

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.

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.

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.

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.

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.

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

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.

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. 

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.

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.

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.

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.

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.