What would you say if I told you that virtually everything you know as a mimosa, isn’t? In fact, the commonly known mimosa is actually an albizzia. Albizzia julibrissin, native from Japan through to the Transcaucuses, was brought to the US back in the 1700s as an ornamental. Back in the day, it was actually thought to belong to the genus Mimosa, but this error was corrected by 1806, but as you can see, old names die hard. Although beautiful, albizzia is a prolific seeder, so is rarely planted any longer.
Interestingly, virtually no one grows any of the 25 North American native species of true Mimosa. Below is our plant of Patrick’s collection of the Southwest US native, Mimosa dysocarpa in flower now. This 3-6′ tall, highly thorny shrub, grows natively from 3,500′ – 6,500′ in the dry deserts of Texas, Arizona, and New Mexico. So far, it seems to be liking its new home in NC. It’s a particularly good food for bees, butterflies/moths, and birds, while the fruit is adored by quails.
Raise your hand if you’ve grown the Southeast native perennial, piriqueta. Piriqueta caroliniana is a little-known Southeast US native that hails from NC, south to Florida. Botanically, it’s a member of the Turneraceae family, after being unceremoniously booted from its previous home in the passiflora family, Passifloraceae. We had never heard of the genus before Patrick introduced us a couple of years ago.
So far, our plant is thriving in our dry alpine garden, where it shares a bed with agaves and other desert denizens. For us, flowering begins in mid-summer, although in more southern climates, it reportedly flowers almost year round. For us, the flower open around lunchtime, and close by 5pm. We’re still testing its winter hardiness, but it sailed through this winter’s 11 degrees F, with no problems.
Since we’ve installed several new bog gardens at JLBG this year, we’ve been experimenting with a number of new bog plants. One wonderful surprise has been Parnassia wightiana, an Asian relative of our native species, P. asarifolia, caroliniana, and grandifolia. The fimbriate flowers have been a real treat to watch. These aren’t the easiest plants to grow, and we were 0 for 9 with the 9 species we’ve tried, prior to building much better bogs, thanks to Patrick’s instructions. We’re now on the lookout for other species that might also thrive in these conditions.
The past couple of weeks the small, freakish flowers of one of the strangest of plants have begun to open in our gardens – pipevines. It’s difficult to believe that nature could summon up anything as strange as the flowers of pipevines. If you remember the “regular” aka actinomorphic and the “irregular” zygomorphic flowers from high school biology then you would have to consider the strange, inflated flowers of pipevines highly irregular.
These plants are related to wild gingers/heartleafs (Asarum) and are members of the basal angiosperms, which are plants with lineages that predate monocots and true dicots. Many of the early angiosperms have flowers that are pollinated by flies or beetles that they lure to the flowers with the pleasant smell of rotting meat or dung. Pipevine is no exception. They trick flies into entering the strangely shaped flowers which often have a funnel-like flare with a narrow opening and trap the fly in a chamber with the pollen and nectar to accomplish pollination.
The general shape of the pipevine flower also approximates the anatomy of a uterus and birth canal. As was all the craze in the early years of medicine, the resemblance to the uterus must mean it is good for treating issues with difficult pregnancies and childbirth. This archaic mode of determining herbal remedies is referred to as the doctrine of signatures – basically if a plant part looked like a part of the human anatomy it would be used to treat ailments associated with that organ. This avenue of medical care led us to the highly unsuccessful use of liverleaf (Hepatica) to treat ailments thought to be caused by the liver, like cowardice and freckles. Medical science has since progressed, maybe?
The pipevines include herbaceous upright perennials, short rambling vines, and enormous lianas (woody vines). The toxic chemical aristolochic acid is contained in all parts of the plant and though it is known to cause kidney failure (which probably didn’t decrease the problems with difficult childbirth) this chemical has also been shown to have antitumor properties. Don’t go munching on the leaves! Pipevine Swallowtails depend exclusively on pipevines for their larval food source and all the species we grow are host to large numbers of caterpillars in the summer.
The Pipevine Swallowtail accumulates aristolochic acid which deters predators like birds from wanting to consume them (they don’t want kidney failure either). This may explain why Spicebush Swallowtails and Red-spotted Purples look so similar to the Pipevine Swallowtail, they’re taking advantage of blending into the poisonous crowd.
These beautiful butterflies always seem to find your pipevines, no matter how secluded you think they are. Don’t worry, we can’t have enough swallowtails and the vines regrow without issue. These are great plants to include in your garden to support our butterflies. The caterpillars have another interesting behavior, when disturbed they have bright orange “horns” that are technically referred to as osmeteria that it pushes out of the front of its body and emit a very foul odor!
Three native pipevines are found in the Carolinas. Common Pipevine (Isotrema macrophyllum) can become a huge liana, reaching the canopies of old-growth trees and spreads through runners and can be difficult to keep contained. It grows best in cool climates and tends to suffer or not grow in warmer parts of the Southeastern US.
Woolly Pipevine (Isotrema tomentosa) grows very well in hot, humid climates and is known from only a few native populations in the Carolina coastal plain. Like its mountain cousin it is very difficult to restrain and may quickly outgrow the space you envision for it.
The only other pipevine is very dissimilar to the others, Virginia Snakeroot (Endodeca serpentaria), which is an upright herbaceous perennial that rarely gets a foot tall. If you’re wondering why these former Aristolochia are now in the genera of Isotrema and Endodeca, well, it appears to all be about genetics. They are closely related but currently in different genera.
One of the easiest to grow and showiest, best-behaved species in our garden hails from Brazil, Argentina and Bolivia, Fringed Pipevine or Fringed Dutchman’s-pipe (Aristolochia fimbriata). The plants form scrambling vines that act more like a groundcover than a vine and have beautifully silver-veined small leaves. The flowers are intricately patterned with lines and fringed with long “tentacles” to create one of the most bizarre flowers you’ll ever include in the landscape. Though you wouldn’t pick a plant from Brazil to be rock-hardy here in Raleigh, this one has been fully hardy (zones 7a-9a). For those of you looking to add some swallowtails but unwilling to devote the space to a monstrous mass of vines this one is for you. Fringed Pipevine is also incredibly drought-tolerant and perfect for part-sun to dappled dry shade.
The ornamental grass genus Bouteloua gained a huge rise in popularity with the introduction of David Salman’s 2010 introduction, Bouteloua gracilis ‘Blonde Ambition‘. While David’s selection hasn’t thrived in our heat and humidity, one of Patrick’s Texas collections has thrived.
Bouteloua chondrosioides hails from West Texas south into Mexico, but surprisingly, doesn’t appear to be in horticultural cultivation. We’ve only had our plants in trial for 1 year, but the 15″ tall clumper sure is looking good so far. Dry, well-drained soil and full sun are the keys for success. It’s in flower this week as you can see below.
This spring, we flowered the highly confused NC native wild ginger, mistakenly known as Asarum memmingeri in the garden. In reality, it’s never been given a proper name, so we refer to it as Asarum sp. nov. Allegheny Wild Ginger. Below, Patrick explains how this ginger was dropped into a botanical abyss, and what needs to be done to return it to proper recognition, and to correct a cascade of past taxonomic errors. -ta
When I was a boy the tiny-flowered evergreen wild gingers that grew all over our land in Alleghany County, North Carolina seemed like they must be a common species, and should have a name. As a boy of 12, however, I had a hard time placing a name on them since they didn’t seem to fit the photographs in popular wildflower books or match the plants that my grandmother’s flora called Hexastylis virgnica (now Asarum virginicum).
I became obsessed with heartleafs as a child and the curiosity remains strong. When I entered college I was lucky enough to take Dr. Peet’s Ecological Plant Geography class at the University of North Carolina, Chapel Hill. Our class, which was all graduate students and me (as a sophomore), was expected to do a project detailing and explaining the range of a particular genus or family of plants. I chose the smooth-leaved evergreen Asarum, then known then as Hexastylis.
I spent the spring semester travelling to every corner of the American South seeking species I didn’t know and trying to fill in the vacant counties in the range maps of those species that I did know. I took countless measurements of calyces and made copious notes on habitat. I was shocked when I travelled to southeastern Virginia to visit the area where Asarum virginicum was likely first collected. These true Asarum virginicum plants were nothing like the “A. virginicum” I was so used to seeing in my boyhood home.
A quick trip to the Earl Core Herbarium at West Virginia University, and later to the Smithsonian, brought to light a serious problem with what botanical taxonomists currently refer to as Asarum virginicum and an even larger problem with what we call Asarum (Hexastylis) rhombiformis and Asarum (Hexastylis) memmingeri.
It seemed as if the Alleghany County plants I had called Asarum virginicum as a child had been mistakenly identified by WVU taxonomist Earl Core as Asarum memmingeri. Complicating this further was that the probable original type specimen for A. memmingeri would later be published under a new name, H. rhombiformis!
To make sense of the cascade of errors, we need to go back further in time. This story begins in 1897 with W.W. Ashe’s publication of The glabrous-leaved species of Asarum of the southern United States in the Journal of the Elisha Mitchell Scientific Society. Here, Ashe describes for the first time Memminger’s Heartleaf (A. memmingeri). From the description it is obvious that he is describing a plant with a very small flower with a very narrow opening (7 mm wide or less).
Error #1 occurred when Ashe described the original type locality as Mitchell County, based on a collection by E.R. Memminger. When I was looking for a type specimen, the best option I could find was a specimen collected (in duplicate) by E.R. Memminger himself that he says in his own handwriting represents the type location. During Ashe’s time, it was not required to designate a type specimen, but the problem was that Ashe’s citation of Memminger’s specimen was actually from Henderson County (“Tranquility”, Flat Rock, NC), not Mitchell County.
Type specimen of Asarum memmingeri collected by E.R. Memminger
Error #2 occurred as we fast-forward to 1987, ninety years after Ashe published his work, when L.L. Gaddy described a new species of Hexastylis that occurs in Southwestern NC and Northwestern SC asH. rhombiformis (Asarum rhombiformis (combination not yet made). In this description he cites E.R. Memminger’s specimen from Henderson County, which, is actually the type specimen of Asarum memmingeri as representing his new species H. rhombiformis. Consequently, the name H. rhombiformis is invalid and this plant should be known as A. memmingeri.
Error #3 occurred when J.K. Small of the New York Botanical Garden, Earl Core of West Virginia University and others annotated (attributed) numerous Asarum collections from West Virginia, Virginia, and NC, of an un-named species that they mistakenly identified as A. memmingeri. Blomquist and all modern authors have since combined these tiny-flowered plants with small openings to the calyx tube within a “catch-all” concept of A. virginicum. Other taxonomists since have followed their mistaken identification of A. memmingeri or A. virginicum for these plants that are known to range from WV south to NC.
We know that these plants that J.K. Small, Earl Core, and others called A. memmingeri actually represent the heartleaf from my Alleghany County childhood homestead and surrounding regions that still has no accepted name.
It is time to clear up the confusion and formally describe these plants along with a new, correct scientific name. For our purposes we will refer to them here as Allegheny heartleaf for a common name (in reference to the mountains, which have a different spelling than the NC county, rather than Alleghany County, NC).
In vegetative form, the Allegheny heartleaf is similar to most of its relatives including A. virginicum, minus, heterophylla, and naniflora. They are tightly clumping with leaves that tend to be as wide or wider than long with a broad cordate base. Though I have found populations with some mottling on the leaves, they tend to lack any variegation altogether.
The flowers on the undescribed Alleghany County heartleaf are much smaller in all dimensions and also differ in the tube constriction from both A. virginicum and true A. memmingeri.
The Allegheny heartleaf is found in typical heartleaf habitat: highly acidic, organic duff beneath oaks and pines and often in association with Rhododendron and Kalmia. They are found along the margins of Southern Appalachian fens and small stream swamps as well as along stream banks and on steep rocky slopes and bluffs that are most often north or east-facing.
The natural range of the species seems to be from Watauga/Avery counties North Carolina, north through West Virginia at low to moderate elevations. In North Carolina nearly all populations are located along the New River drainage, though there are outliers along the Yadkin River drainage downstream to Donaha Bluffs in Forsyth County. This taxa is tightly tied to the Appalachian range with outliers into the piedmont in areas with cool microclimates along rivers that originate in the mountains. Between the mountain populations of Allegheny Heartleaf and the coastal Virginia Heartleaf (Asarum virginicum) occurs A. minus, which largely replaces Allegheny Heartleaf in most of the piedmont of North Carolina.
Allegheny Heartleaf was very difficult for me to grow, even in seemingly hospitable microclimates in Clemson, South Carolina. It seemed to survive but only for a short time, gradually declining and producing dwarfed leaves by the 2nd season and then disappearing by the 3rd. I am extremely pleased to have this species growing strong, flowering and producing normal sized leaves for its second season here at Juniper Level Botanic Gardens.
What needs to happen is for Hexastylis rhombiformis to have a name correction to Asarum memmingeri, and for the plant widely known as Asarum memmingeri to finally be named for the first time, hopefully with a specific epithet named for the Allegheny Mountains, which incorporate the heart of its range.
This week, we fielded a call from our garden staff that there were large yellow jacket (Vespula maculifrons) nests in several arborvitae near where they were working. Knowing how aggressive and toxic the stings of these native vespid wasps can be for humans, they had requested help in getting the nests eliminated.
When Patrick arrived to check out the problem, he noticed that instead of finding nests, the yellow jackets were actually feeding on the arborvitae. Since this species of arborvitae was currently in the midst of pollen and cone production, there also appears to be some type of resin being exuded at the same time, which is a delicacy for the yellow jackets.
We estimate there were between 100 and 200 yellow jackets per plant. Because they were busy feeding, they had no interest in us, despite our close up study of their behavior. Our entomologist, Bill Reynolds, who had observed this phenomenon before with vespid wasps and arborvitae, showed us that we could actually touch the yellow jackets without drawing their ire. This is certainly not the case if you’ve ever been anywhere near a yellow jacket nesting site.
The other interesting phenomenon is that despite being Eastern US natives, the yellow jackets were only interested in the Asian arborvitae species, Platycladus (Thuja) orientalis. Growing adjacent was the East Coast and West Coast arborvitae, Thuja occidentalis and Thuja plicata, but neither attracted a single insect. This is another nail in the coffin of that oft repeated myth that only native plants feed native pollinators. One of many lessons here, but it’s especially important not to spray first and ask questions later.
We are pleased to announce that Dr. Patrick McMillan’s new book, A Guide to the Wildflowers of South Carolina, has been published. While Patrick taught at Clemson, he was approached to update The Guide to Wildflowers of South Carolina (Porcher), first published in 2002.
After studying over 200,000 herbarium sheets (dead, smashed plants), and making countless trips into the field to photograph and study the plants in habitat, the updated book, A Guide to the Wildflowers of South Carolina has been born. This amazing 613-page book is a dramatic update from 2002 version, complete with more images, completely revised distribution maps, and an additional 200+ plant species.
I have known Patrick for over 30 years, and we are so blessed to have him as our JLBG Director of Horticulture and Gardens. We are the beneficiary of his encyclopedic plant knowledge every day, but now everyone can benefit from that same knowledge through this amazing new book.
His new book, which has an official publication date of next month, is available through your favorite on-line bookseller. Whether you live/travel, or botanize in NC, SC, or any of the Southeastern states, you will find this book invaluable.
If you get your gardening information on-line, where everything written is a fact, you’ll know for sure that acacias aren’t growable in Zone 7b, Raleigh, NC. If that includes you, don’t look at the photo below of Acacia greggii ‘Mule Mountain’ in flower at JLBG. Acacia greggii is a native from Texas west to California. Our seven year-old specimen is from Patrick McMillan’s collection in Cochise County, Arizona.
To be nomenclaturally correct, most of the US Acacias have now been moved into the genus Senegalia, so even though the American species aren’t from anywhere near Senegal, this is now known as Senegalia greggii.
Of course, it you also read the hogwash on-line about native pollinators needed and preferring plants they evolved with, then you’ll also have to ignore the masses of native bees that cause the entire plant to buzz while they’re feeding. It’s good we don’t let our plants and insects read books or the Internet.
Please join me in welcoming our newest JLBG team member, Dr. Patrick McMillan. I’ve known Patrick for 30 years, going back to his days as a student at UNC-Chapel Hill, and long before he became a legend in the plant world.
We’ve followed his amazing journey, most recently as Director of Heronswood Gardens in Washington. Prior to that, he was Director of the SC Botanical Garden and Professor of Environmental Sustainability at Clemson since 2000. Patrick was the Emmy Award winning host of the renown PBS series, Expeditions with Patrick McMillan. Patrick is a highly-respected botanist/naturalist, who has won far too many awards to mention, but we’ll let Patrick tell you a bit more about himself and why he decided to partner with JLBG.
My first experience with Juniper Level and Tony was sitting at the kitchen table in 1991, the inaugural year of Plant Delights Nursery, talking about Asarum and star-struck by Tony’s knowledge and passion that has continued to grow into one of the world’s premier gardens and nurseries. In those days I dreamed of the opportunity to work alongside such talented horticulturalists and intrepid explorers.
My love of plants and all things slithering, creeping, crawling, and flying came at a very early age. I can’t remember a time when my life wasn’t centered on them. Fast forward 31 years and I found myself sitting at the same table reminiscing about the past, marveling at how far JLBG has grown, and stirring excitement for the future. I am so enthusiastic about joining the staff at JLBG, learning from the lifetimes of incredible knowledge and skill that is assembled among the employees and sharing my own experience, passion, and knowledge to bolster the mission and the horticultural and conservation accomplishments of this magical place.
I’m probably best described as a plant nerd. I have never met a plant I didn’t love. Every plant has a story and each is connected to our lives and the lives of the biodiversity upon which we all depend. Much of my horticultural experience and focus in South Carolina and at Heronswood Garden in Kingston, Washington has been focused on generating and supporting insect, bird and other wildlife diversity in the home landscape.
My philosophy of natural community gardening and the generation of life is a fairly simple one based on filling every space with life – diversity generates diversity. My exploration of the plant world has taken me from pole to pole and over every continent except Australia. I was trained as a sedge taxonomist but my interests include anything with cells. I’ve described new species ranging from ragweeds to sedges and begonia.
I also believe strongly that our greatest gift is sharing knowledge and I have worked as a lifelong educator. You may also have seen me on your local PBS station, where for 15 years I wrote, hosted, and produced the series “Expeditions with Patrick McMillan” – distributed by American Public Television. Conservation, preservation and generation of life is at the core of my life’s mission and I can imagine no better place to be nested within than JLBG. I hope to meet you soon and share some hearty plant nerd conversation.