This week for Flora and Fauna Friday we have the cradle of Carolina’s Monarchs, Aquatic Milkweed (Asclepias perennis).
Aquatic Milkweed is found throughout the Lowcountry, ranging from South Carolina west throughout the southeastern coastal plain and north up the Mississippi River valley. It’s a perennial wildflower that grows in bottomland forests, floodplains, and the mazes of ditchwork and backwaters that permeate and diffuse them. Moist, rich soils that flood seasonally are a must have for its natural niche. Aquatic Milkweed grows to knee height in small clumps of singular stems. These stems are stacked with opposing pairs of narrow, blade-like leaves from base to leading bud. Come late May and through the end of July our Milkweed blooms.
Two to three dozen individual, pure-white flowers emerge together into a ball atop the tip of the plant. Each flower bears that unmistakable Milkweed shape: an hourglass of petals, five facing up in a tight packed bundle around, anthers and ovary, and five swooping down below into a showy skirt to catch the eye of passerby pollinators. New balls of flowers are merged beside the old, refreshing the display throughout the season and expanding across the stand of stems. Aquatic Milkweed flowers are a bright white beacon, a lighthouse standing amidst and shining across a choppy sea of green, cutting through the suffocating umbral umbrella of a bottomland forest. But what does the beacon beckon? It brings in butterflies! Most importantly the Monarch butterfly (Danaus plexippus).
Monarchs rely on native Milkweed plants to serve as nursery and nourishment for their caterpillars. Milkweed plants contain toxic compounds that ward off most herbivores. Monarchs have taken advantage of this, making themselves immune to the poison while also packing it into their own bodies as caterpillars, to serve as a lifelong shield against birds, lizards, and other predators. Monarchs are on the decline throughout much of the Unites States right now. They are even a candidate for federal listing as a threatened species. Their decline is due to impacts on all fronts at all stages of their life cycle. Monarchs are migratory, a trait that makes them resilient to large seasonal changes across a large landscape but simultaneously vulnerable to chronic, widespread habitat degradation or loss of critical refuge habitats. The most chronic threat they are facing comes from the widespread loss of Milkweed on the landscape over the last fifty years. Monarch caterpillars can only eat Milkweed. Without it, they will perish.
Here in South Carolina, Aquatic Milkweed is the most important host plant for our Monarchs. Its populations in our remote blackwater swamps are stable and consistent. Thus, Aquatic Milkweed provides a dependable network of host plants that our Monarchs rely on every spring. In fact, it’s so dependable many of our Monarchs in South Carolina no longer migrate! Well they still do, just not very far. From beaches to bottomlands, that’s as far as they go. Our Lowcountry Monarchs winter in the thermally insulated maritime forests of our beachfront barrier islands and our sheltered Sea Islands. Come spring they sail a couple dozen miles upriver, settling in the swamps and bottomlands of our blackwater rivers. There they lay their eggs upon Aquatic Milkweed and pass the mantle to the next generation. This new crop of Monarchs then disperses throughout our state throughout the year and makes use of the great diversity of Milkweed species found across our landscape. Then their children, or grandchildren, complete the circuit and return to their shelter by the sea to weather another winter.
If you’d like to learn more about the Lowcountry’s resident Monarch population, you can check out the research paper behind this discovery here:
https://www.nature.com/articles/s41598-023-37225-7.pdf
This week for Flora and Fauna Friday we have a bejeweled beetle in a thatch hat, the Palmetto Tortoise Beetle (Hemisphaerota cyanea).
The Palmetto Tortoise Beetle is found throughout the Sea Islands of South Carolina and Georgia, ranging south throughout all of Florida and west along the immediate Gulf Coast to Texas. They spend their life entirely on our native palms, including Cabbage Palmetto (Sabal palmetto), Dwarf Palmetto (S. minor), and Saw Palmetto (Serenoa repens). Upon the palms they slide up and down the fronds making their meals by scraping out the softer flesh from between the stringy fibers of the leaf. The Palmetto Tortoise Beetle is a captivating critter that deploys two fascinating defensive strategies throughout its life.
Adult beetles are a quarter-inch in length, dome-shaped, dimpled like a golf ball, and gleaming with a deep metallic blue-green that borders on black in the shade. Tiny orange antennae are their only contrasting color. The adult’s primary defense from predators is turtling up and tanking hits. Their shell is thick and its dimples provide extra structural reinforcement. Its glass-like texture and well-fit joints permit no handholds for prying predators. Even further, they have an iron grip. Their feet are modified into flat brushes. These furry feet are so finely divided that they electrically adhere at the sub-atomic level to a palmetto frond. It’s the same way lizards, like anoles and geckos, can scale plate glass, just shrunk down onto an ironclad arthropod. This makes Palmetto Tortoise Beetles functionally immune to being plucked from a palm frond by a passing bird or blown away by hurricane force winds. But as a young’un they have a far more juvenile form of defense.
Larval Palmetto Tortoise Beetles protect themselves from would-be assailants the same we protect ourselves from the sun, with a big straw hat. Only difference is our Beetle makes its hat from poop. How lovely! The first thing a baby Palmetto Tortoise Beetle does when it crawls out of its egg mass of a crib is start chowing down on a palmetto frond. The second thing it does is number two. The larvae will excrete long strands of what’s basically paper, compressed pulp pulled from the palmetto. Each strand is then glued to its back when complete and stacked atop the next. These strands twirl around into a basket that fully shields the larvae. This is called a “fecal thatch” and it helps shield the larvae from the elements and predators. Unlike the adult beetle, the larvae lack atomic Velcro feet. Instead they have sharp hooks that dig under the fibers of the palm frond, anchoring them like a roller coaster to its rail. When harassed, the larva hunkers down and waits for the predator to pass, hoping it loses its appetite as it vainly attempts to penetrate the fecal thatch. The larva carries this thatch with it throughout its life, even as an immobile pupa, until it matures, puts its childish past behind it, and dons a suit of armor instead.
This week for Flora and Fauna Friday we’re hosting a globe-trotting cosmopolitan herb, Common Yarrow (Achillea millefolium).
The genus Achillea, the Yarrows, has well over a hundred species globally within it. Three are found in North America but only one is native and widespread in the United States. Common Yarrow (A. millefolium), or just simply Yarrow, is found in all fifty states and essentially all of South Carolina. It’s not often an easy plant to find out in the wild but it is quite easy to pick out of a crowd when you do. Its feathery leaves, so finely divided to appear as a fluffy green haze, project half-a-foot up through grass and duff in search of light, forming a dense dome of leaves in good conditions. In the frost-free reaches of the Sea Islands, Yarrow even grows as an evergreen, spreading underground through its perennial web of roots into a cluttered groundcover. In early spring stalks rise skyward, plateauing at knee height into an umbel of small white flowers, crowded shoulder to shoulder. These flowers appear in late April through the end of May and are pollinated by all manner of small flies, beetles, and bees. Yarrow is very drought tolerant and hardy. In my opinion, it’s one of the easiest perennial plants to grow in any garden.
Common Yarrow has long been a staple in formal gardens, floral arrangements, herb beds, home remedies, and traditional ethnobotany. The leaves of Yarrow contain astringent compounds, the effects of which have been known since prehistory and have been relied upon by humans ever since. The astringency of Yarrow causes blood vessels to restrict and contract wherever it is applied to the body. This reduces swelling and slows bleeding, helping heal wounds, reduce pain, and break fevers for many minor ailments and injuries. The Greeks used it as a wound dressing in their armies and credited the legendary hero Achilles with discovering its medicinal properties. Fittingly, Yarrow received its genus name “Achillea” from this Greek myth. Yet, the utility of Yarrow was known long before Greece. Yarrow was ancient Ibuprofen, a wonderfully utilitarian plant prescription. This made it an invaluable asset in every culture that encountered the efficacy of Yarrow. Where those peoples subsequently traveled to, they brought Yarrow seeds in tow and sowed them freely around their villages and farms. When those people left or perished, the Yarrow persisted and often prospered.
As you might surmise, this has transformed Common Yarrow into a well-traveled wildflower with quite the tale to tell. From Iberia through Siberia, over the Bering Strait to Alaska and all the way to the Atlantic ranges Common Yarrow. This singular species calls nearly the entire Northern Hemisphere home! Down south it can be found growing freely across South America, Sub-Saharan Africa, and Australia. What brought it here is clear: the hands of man. But from whence it came and when it began to wander around the world, and where it is truly a wild flower, rather than a waif, is far from clear. To call the natural history of Yarrow complex would be a thorough understatement. For tens-of-thousands of years, practically as long as people and Yarrow have occupied the same space, humans have been intentionally collecting, prescribing, planting, and spreading Yarrow across the globe. All the while relict clumps of Common Yarrow have been advancing and adapting themselves to new locales on their own volition. This has created a species-complex like none other, a botanical boogeyman rendering night terrors unto today’s native plant enthusiasts.
A species-complex is exactly what it sounds like. It’s a species that is complicated and defies traditional scientific classification. Yarrow is the definition of a species complex, but cranked up to eleven. There are native, “true” wild-type Yarrow plants on the landscape within its original home range. Trouble is we don’t know where that is or which exact strain is the wild-type, but it is somewhere in Europe, probably. From there we have the species’ many ancient introductions across the northern hemisphere where they have naturally adapted to the unique ecosystems in their new homes. In parallel we have the millennia of heirloom cultivars bred and grown by cultures across the world. Then came the traditional European cultivars, which were spread globally during the renaissance and with colonization to most of the Southern hemisphere for gardens and cattle forage. Then lastly the modern cultivars of Common Yarrow developed in the last hundred or so years with precise artificial selection for horticultural use, again grown globally. All of these different chronological steps for every subspecies, strain, cultivar, and variety now exist simultaneously on the landscape, planted next to each other in fields, farms, and garden beds. Of course, they all hybridize with each other with varying degrees of regularity. Let’s not even mention the further complications of the polyploid plants. This all has created a vast gradient of gray area into which we must wade to answer the question, “Is Common Yarrow native to North America?” The curious case of Yarrow shatters the false dichotomy of the question. It is both exotic and native at the same time in the same place. Each individual plant occupies a space on a spectrum somewhere between either extreme.
This week for Flora and Fauna Friday we have the king of the cane, the piper over the palms, the Swainson’s Warbler (Limnothlypis swainsonii).
Past the break of winter, beside the brake of cane, a spell of birdsong suddenly sunders the silence in the stagnant steamy air. A brown blob at the bend of a branch beelines below the bamboo. Switchbacks through Switch Cane it snakes swiftly into a sightline, sneaking peeks to guess your intent before dissolving into the shadow of the thicket; a Swainson’s Warbler patrolling his kingdom of cane.
Among our Warblers in family Parulidae, the Swainson’s Warbler stands out for its stout frame, sharp and sturdy bill, and muted plumage. Unlike the radiant golden Prothonotary and Hooded Warblers or the contrasting bi-chromatic Black-and-white and Yellow-throated Warblers, all of which are neighbors in the spring bottomland forest, Swainson’s Warblers instead don a cryptic cloak of camouflaged colors. Their back is bronzed-brown and belly olive-stained-ivory. A dark stripe runs through the eye, a pale eyebrow borders above and is capped with a crown of chestnut. Not a fleck of extra color to stand out against the standing timber’s shadows. What the Swainson’s Warbler lacks in prismatic presence it makes up for with its pipes.
The song of the Swainson’s Warbler is a short verse of sharp whistles: three flat notes slowly rising, a fourth cut short jumps high and falls low, “Tea, Tea, Tea, Te-wi-two”. Although easy to hear it’s a hard song to commit to memory, falling lyrically somewhere between the tunes of the oft adjacent Louisiana Waterthrush and Hooded Warbler. Despite being readily heard when present, Swainson’s Warblers are hard birds to find and even harder birds to lay eyes on.
Swainson’s Warblers are found across South Carolina in summer. Yet, they are secretive birds, singing low below heavy canopies and just barely above dense thickets of bushes, bamboo, and palmettos amidst the depths of blackwater swamps, heath thickets, and bottomland floodplains. Even within these vast and nearly inaccessible ecosystems, breeding pairs of Swainson’s Warblers are often few and far between. Swainson’s Warblers are a species of conservation concern across much of the Southeast. Conversion of floodplain forests to agricultural fields and intensive hardwood timbering and pine planting of floodplains have supplanted or upset the delicate balance of these ecosystems. This destabilizes the palmetto thickets and canebrakes in the coastal plain that Swainson’s Warblers rely on to nest. Without consistency in these wetland systems their populations have fluctuated and shrunk for over a century, making them a species in need of special attention. Thankfully the forever protected floodplains of the lower South Edisto River remain a stronghold for the species, where Swainson’s Warblers still peacefully reign over the cane.
This week for Flora and Fauna Friday we look longingly towards the bountiful boughs of Red Mulberry (Morus rubra).
Red Mulberry is a small midstory tree found in forest understories throughout all of South Carolina and the Eastern United States. Here on the Sea Islands, I most often find it reaching about thirty feet in height, squarely within the midstory below a hardwood canopy, and growing on well-drained but moist and fertile upland soils. Its growth form is an umbrella, with long arching boughs towering and spreading upward into a dome-shaped canopy. Each sinuous limb holding aloft emerald-green leaves often as large as an outstretched hand. These leaves have a rough, scaborous texture on the hand, like sandpaper. Their shape is also highly variable. Red Mulberry leaves are trimorphic in nature, having three distinct shapes. They can either be a nearly circular swollen heart-shape with a small pointed tip, or instead a three-lobed form falling somewhere between the shape of a fleur-de-lis and a trident or, lastly, somewhere in between with the shape of an oven mitt. These trimorphic leaves are incredibly distinct and make Red Mulberry easy to identify in the wild. When its leaves are lacking in winter, that arching trunk and the rather smooth, finely fissured dull-gray bark gives this tree’s identity away to the perceptive naturalist. Yet, the most defining feature of Red Mulberry is its fruit.
In April, Red Mulberry begins to bloom with its small and pendulous pale-green catkins dangling from every leaf node down its limbs. These wind pollinated flowers are easy to miss and short lived. Once pollinated the flowers mature into a clustered fruit, similar in shape to an elongated raspberry or blackberry. Within the span of a few weeks these fruits rapidly ripen, turning from pastel-green to pink, then ruby-red, and eventually purple-black when fully ripe. These fruits are short lived on the limb and a favorite food of every animal in the forest. Red Mulberry fruits are plucked as fast as they can mature by every patrolling songbird. The few that mature and make it to the ground are soundly sucked down by any passing quail, turkey, turtle, deer, fox, squirrel, opossum, or raccoon that chances upon them. Red Mulberries are a tremendous spring food source for practically every forest creature. These fruits are edible for humans as well and apparently quite good. However, I can’t personally provide commentary myself. Despite having a Red Mulberry tree in my own yard, I’ve never once eaten a fruit off of it. The critters never leave me any to try!
We have a second species of Mulberry here in the Lowcountry as well, the White Mulberry (Morus alba) which is an exotic species introduced from Europe. It’s easily told apart by from Red Mulberry by its leaves, which are a bit smaller, smooth to the touch, and in their lobed forms take on a more fig-like appearance. Its bark is usually paler and its fruit more variable in color once mature, averaging more towards a pale-red. White Mulberry is most often found in urban areas and the margins of major highways and railroads, where it has escaped from yards and gardens thanks to birds spreading its seeds. White Mulberry can become invasive in areas of high disturbance with little natural habitat. Yet I rarely see it causing issue in wild areas of the Lowcountry. It more so fills a void left in the wake of industry and sprawl.
This week for Flora and Fauna Friday we’ve stumbled upon the mock moccasin, the Banded Watersnake (Nerodia fasciata).
Watersnakes, as the name implies, are a genus of aquatic snakes that spend their days in the swamps, rivers, ponds, and bays of the Carolinas hunting fish, frogs, salamanders, and aquatic invertebrates. During the day they can most easily be found sunning or lounging on stumps, fallen logs, shrubs, culverts, rocks, and banks in or along wetlands. Often they are more active at night, hunting croaking frogs and sluggish fish under the cover of darkness. Once supper is caught, Watersnakes swallow their prey whole and alive without venom or constriction.
Although the Banded Watersnake is my focus for today, I’d like cover our other Watersnakes in brief detail. Here in South Carolina we have five species of Watersnake: the Banded Watersnake (Nerodia fasciata), Plain-bellied Watersnake (N. erythrogaster), Green Watersnake (N. floridana), Brown Watersnake (N. taxispilota), and Northern Watersnake (N. sipedon).
The Northern Watersnake is restricted to the upstate here in South Carolina, where they live in a wide array of aquatic habitats, particularly streams, rivers, lakes, and ponds. They grow to about three feet in length and have a body patterned with a checkerboard of alternating brick-red squares over a base of coppery bronze. Their diet consists of a diverse array of amphibians and small fish.
The Brown Watersnake is found throughout the coastal plain of South Carolina and is specialized to a life living in major rivers, as well as the reservoirs, streams, swamps, and oxbows along their courses. They often reach four feet in length and their body is checkerboard patterned, with dark walnut-brown blocks atop a base of neutral-brown. They are strong swimmers and piscivorous, specializing on a diet of fish, with a strong preference for catfish.
The Green Watersnake has the narrowest range in the state out of our five Watersnakes, being found only in two disjunct areas: the backwaters of the central Savannah River and the swamps of the lower coastal plain from the Waccamaw to the Edisto River. They are specialized to a life patrolling still or slow moving freshwater marshes. They average three to four feet in length and have a body colored a dark olive-green with narrow zig-zags of black crossing their back. Their diet consists mainly of fish and frogs.
The Plain-bellied Watersnake is found across nearly all of South Carolina and lives in a wide array of habitats and wetland systems. They are highly mobile on the landscape and can be found more readily than other Watersnakes in ephemeral wetlands, floodplains, isolated ponds, pocosins, ditch systems, or out in the uplands trekking between wet areas. They readily grow to three feet in length and are distinctly colored, with a dark ruddy-brown back and a belly as orange as Carolina clay. Their diet is skewed more towards frogs than fish, on account of them often hunting in fish-free ephemeral and isolated wetlands.
The Banded Watersnake, our focus for today, resides throughout the coastal plain of South Carolina. They can be found in practically every freshwater wetland system in the Lowcountry, from major rivers and lakes, to expansive blackwater swamps, to ephemeral pools and suburban drainage ditches. They are our most abundant Watersnake here on the Sea Islands. Being as widespread as they are, the Banded Watersnake’s diet is equally diverse but, like our other Watersnakes, consists primarily of frogs and fish. They generally grow about two-and-a-half feet long and can be quite varied in coloration and patterning. Often, they have a reddish-brown body ringed in bands of ebony black. With age and size, these bands often blur together turning the snake nearly black across the back.
All our Watersnakes are non-venomous and no threat to man nor pet. However, they often have a short temper and a bad attitude that has not helped them escape undue persecution. Watersnakes mimic the venomous Cottonmouth (Agkistrodon piscivorus) when threatened. They flatten their heads into a broad triangle to resemble a Viper and coil their bodies into a threatening posture. Their keeled scales, a trait they share with our Vipers, help them complete their menacing look. Yet, if you look closely, they lack the vertical “cat’s eye” pupils of a Viper. If approached or touched Watersnakes generally bite without hesitation. This is all just a bluff to convince you to let them be. The Banded Watersnake is a particularly good mimic as it is the same size, body shape, and a similar color and pattern to the Cottonmouth, with which it overlaps in range and habitat. Sadly its success as a mimic leads to a lot of Banded Watersnakes being mistaken for Cottonmouths, and then pointlessly killed by people every year.
As I’ve said before, and will say again, snakes aren’t out cruising around looking for people to bite. Just think about it for a second. Even our largest snakes here in South Carolina can’t eat anything bigger than a squirrel. Why would they risk life and limb (well maybe not limb) harassing humans and dogs? The vast majority of our snakes are nonvenomous and so the vast majority of snakes killed each year are harmless. Even with the Vipers, most snake envenomations are caused by people trying to pick-up, move, or kill a venomous snake. A snake’s primary defense is camouflage; they freeze and pray you don’t see them. If you spot them, the jig is up and they will attempt to flee into cover. But if escape isn’t possible and or they are cornered or grabbed, biting is the only chance they have to save their scaly hide. A snake doesn’t know your intentions, and every day in nature is filled with life or death dilemmas for wildlife. All the snake knows in this situation is that it may only have seconds left to live. Can you really condemn a creature for just wanting to stay alive? Spare it the spade! If you find a snake in the wild, leave it be. Appreciate it, photograph it, but let coiled snakes lie.
This week for Flora and Fauna Friday we find swaying in the sea breeze the blooms of Beach Sunflower (Helianthus debilis).
Beach Sunflower, sometimes called Cucumberleaf Sunflower, is a species native to all the Gulf States and found throughout Florida. Thanks to man it has moved its way up the Eastern Seaboard and now calls most barriers islands in South Carolina home. Beach Sunflower is a subtropical species, growing as a perennial where winter freezes are scarce and mild. Yet, in colder climes it can persist as an annual thanks to being a prolific re-seeder. Beach Sunflower has a very low growth-form for a Sunflower, growing as a bushy groundcover with creeping stems just ankle high above the ground. This is an adaptation to resist strong and sustained winds. Its leaves are opposite and triangular in shape. Its flowers grow low as well, not much more than a foot above the soil. Their flowers fit the traditional mold for our native sunflowers. An ebony-black disk, flecked with the lemon-yellow light of anthers is ringed in dozens on golden yellow petals to produce a showy two to three inch compound flower. In late April, the flowers of Beach Sunflower begin to appear here in South Carolina. They provide a bounty of pollen and nectar to our native bees, butterflies, and other pollinators from spring to throughout the dog days of summer.
Beach Sunflower is one of those species that sits squarely in the gray area between exotic and native, being native to the southeast but not to South Carolina specifically. Regardless, it has found its way into a niche here thanks to its drought tolerance, heat resistance, and ability to survive on infertile, sandy soils. This allows Beach Sunflower to grow within the dune systems of our beaches, providing a splash of color and a pocket of pollinator habitat alongside our native flora. It also does well in cultivation and can be a valuable asset to butterfly and pollinator gardens on weathered sand ridge soils or in urban areas.
This week for Flora and Fauna Friday we find washed ashore a scribbled scroll of shell telling a tale from our natural history, the Lettered Olive (Oliva sayana).
The Lettered Olive is found from North Carolina west to Mexico living near-shore along sandy bottomed inlets and beaches. Lettered Olives are marine snails, in the Gastropod order with slugs and land snails. Lettered Olives grow up to two-and-a-half inches in length. This makes them one of the larger marine snail species found here in South Carolina. Their thumb-sized shell is pill shaped with an obtuse point on one end and a long, narrow opening, called an aperture, running almost the entire length of their shell.
Through this aperture the Lettered Olive interacts with the outside world. From the blunt end of its shell it extends its head, the tube-like siphon it uses to breathe, its sensory tentacle, and its broad, ribbon-like foot which fills the full length of its aperture. Lettered Olives are particularly abundant on the beaches of South Carolina. This is thanks to the height of our tides and the dynamic conditions of our inlets and shoreline. This concentrates the sea life that depends on shallow, sandy waters into the surf zone. Most importantly, this creates the perfect habitat for the small Coquina Clam (Donax variabilis), a favorite food of the Lettered Olive. Our Lettered Olive is a prodigious predator that patrols surf swept beach sands, plowing just below their surface in search of Coquina and crustaceans. When an Olive stumbles onto a suitable snack, it surrounds and smothers it with its sinuous sole and sinks below the sand to savor its seafood supper. Safely below the beach it slowly shreds its dinner with its rasp-like tongue, its radula, as it holds and digests it within its foot.
The Lettered Olive’s shell is unique not only for its shape but for its pattern and finish. It gets its common name from the hieroglyphics scrawled along the length of its shell. Runes written on the rolled scroll of its form tell the tale of its life, its history penned upon its very body. These glyphs are inlaid below the gloss of its glazed exterior. This uniquely pristine porcelain façade on a snail this large is thanks to the polishing performed by its expansive mantle. The mantle of a mollusk builds its shell as it grows. Most species keep their mantle tucked inside the aperture, out of harm’s way. Lettered Olives instead sheath the mount of their shell with their mantle as they burrow beneath the sand, burnishing its exterior to a high gloss and sparing the shell from the scouring of coarse sand.
Lastly, we have a pair of fun facts. The Lettered Olive was first described to science in 1834 from South Carolina by Dr. Edmund Ravenel. Dr. Ravenel was one of the founders of MUSC and one of the first naturalists to study shells in detail, a field he helped pioneered that today is known as conchology. One-hundred-and-fifty years later, in 1984, the Lettered Olive was made the state shell of South Carolina.
This week for Flora and Fauna Friday we have an imperiled tree that, like sand sliding off a bluff, is silently slipping away from our Sea Island landscape, the Bluff Oak (Quercus austrina).
Bluff Oak is a small oak growing to roughly sixty feet in height. Its trunk is straight and sheathed in fine flakes of platinum-white bark. Often that trunk is blemished with small burls or studded by small low-hanging limbs blending upward into a tall crown. The deciduous leaves of Bluff Oak are a rich emerald-green and feather-esque in shape. These leaves are the length of your outstretched hand but relatively narrow and pointed, with seven-or-so irregular, shallow lobes. They’re not the easiest oak to identify. Yet, their twigs are reddish brown with strongly pointed buds. This is a subtle feature that helps separate them from their closest relatives among the white oaks. Their lime-green acorns are fairly large and sought after by deer and turkeys, if the squirrel and Jays don’t claim them first.
Bluff Oaks grow in the Deep South from Mississippi to North Carolina and down through North Florida. Yet, they are known from only a smattering of trees from a handful of counties in each state. They’re most often encountered perched on a bluff overlooking a marsh or river. Here on the South Carolina Sea Islands, fertile well-drained soil in maritime fringe forests in view of the marsh and with a stable shallow water table seems to be their preferred natural habitat. But that comes with a caveat. Bluff Oaks are weird.
Very few people, if any, have a good handle on what makes Bluff Oaks tick in their natural habitats. They occupy a very narrow niche in the Sea Island ecosystem. A niche that was historically quite stable but today quite rare due to the meddling of man. You see, Bluff Oaks love to live on bluffs, with a panoramic prospect of the marsh or a view down a bend in the river. But that’s most people’s favorite place to live as well! That’s bad luck for the Oaks. Untold scores have been clear-cut for waterfront development over the last 75 years. Many of the mature Bluff Oaks still alive today are nestled quietly in people’s yards, on church grounds, near boat landings, or on old government lands along rivers. Long before large-scale residential development began sweeping through the South, Bluff Oaks were imperiled by logging and agriculture. Clearcutting for fields on fertile sands removed mature trees from all but the bluff margins. Bluff top plantation houses displaced them further. The old trees that survived on the landscape then had the stability of the shallow water pulled out from under them by ditching and diking. Drying or flooding the few trees still hanging on. Their progeny subsequently clung to cliff faces, marsh margined peninsulas, and remote islands that were too impractical to farm and which foresters found inconvenient to plant in pine. Many of the surviving Bluff Oaks were likely intentionally spared the axe, due to their compact growth and long crown making them unfit for lumber, and thus not worth the fuel to haul to the mill. Or that’s the history I at least surmise led to their near demise.
Bluff Oaks were rare to begin with, grew in inconvenient locations to access, and had little economic value. So people paid them little attention. Meaning we have a very poor understanding of what their historic range used to be. Now that there are so few left, it’s incredibly difficult to fit enough puzzle pieces together to see the full picture of their ecology. I suspect they’re a botanical relict of a bygone time. An arboreal artifact from an ancient age, likely a species that thrived before the last ice-age, compressed by climatic swings and then pushed towards the brink by our hands. The Bluff Oak’s distribution is incredibly disjointed, with tens or hundreds of miles between populations. Those populations are rarely more than a half-dozen trees. Most are just one or two trunks. Less than ten sites are known with more than ten trees. That means there is next to no gene flow between populations. Often, there are no saplings growing that can replace mature trees when they perish. They are a declining species on the path to oblivion.
But all hope is not lost! Bluff Oaks actually do well as a shade tree in coastal suburbs and developments. They even thrive when reintroduced to their natural habitats on bluffs and banks. We haven’t pushed this species off the bluff yet! There is a space for them in the modern world. We just need to lend a helping hand. Right now, there is active research underway led by the North American Land Trust, in partnership with the US Forest Service and several Arboretums, to collect acorns and scionwood from Bluff Oaks across the country. These acorns and grafts will be grown out into mature trees as living seed banks. The USFS is even starting a nursery for Bluff Oaks in SC within the Francis Marion National Forest. The acorns produced by these nursery and specimen trees will be used for conservation of the species across the Southeast.
You can help in this effort too! The most important thing this research needs help with is finding new Bluff Oak populations. Currently, only one single site in Charleston County is known with surviving Bluff Oaks. Those seven trees are standing proud today on one of EIOLT’s conservation easements, right here on Edisto Island. Which means there very well might be a Bluff Oak standing on the edge of the woods right outside your window! If you think you know where a Bluff Oak is, anywhere in South Carolina, please reach out to EIOLT with the location of the tree and take some photos of the bark, leaves, and twigs if you can. We’d love to document its location, collect acorns, and help save this imperiled species.
Bluff Oak seedlings are not currently readily available anywhere for purchase for transplantation. At least not anywhere I can find online. But I’m hopefully that, in the not so distant future, they will be. And that this handsome hardwood can once again grace the banks of Edisto Island. Waving with Spanish Moss over our waterways, shoulder to shoulder with Live Oaks and arm in arm with Edistonians.
If you’d like to learn more about this research and restoration effort, please check out the below links:
https://www.internationaloaksociety.org/content/seeking-quercus-austrina-conservation
This week for Flora and Fauna Friday it’s our other red bird, the Summer Tanager (Piranga rubra).
Draw a line to a branched tine high in a pine and there you’ll find birds that shine bold of ruby and gold. With the end of winter’s cold, stepping into spring’s hold, summer’s Tanagers are pulled to the Lowcountry; they fall upon our forests once more. Summer Tanagers are part of the Cardinal family, Cardinalidae, which contains some of our most stunning songbird species. Our Summer Tanagers are no exception here. Males radiate a deep and vibrant scarlet-red across their entire body, contrasted only by beaded black eyes and a bone-yellow bill, heavy and faintly down-turned. Females are stunners too, with feathers saturated a saffron-yellow over undertones of olive-green, which shows most strongly through their wings.
Summer Tanagers spend the winter in the tropics of Central and South America. They return to the Southern United States around the spring equinox, reaching the South Carolina Lowcountry on the first week of April most years. Upon arrival, they begin establishing territories in wooded locales. They prefer patrolling open woodlands, savannas, maritime forests, field edges, and park lands. Places with wide spaced trees or an uneven low canopy. On the Sea Islands, males most often perch atop a Live Oak or pine and begin singing their own praises, a jumbled, oscillating whistle that echoes over the forest, a sonic fence to stake a claim of land. When not mending fencing or disputing borders, Summer Tanagers can be heard moving through the treetops uttering a trademark “pi-tick” call or chattering “pi-ti-tu” as they go.
Summer Tanagers are leaf gleaners and hawkers, scanning limbs and twigs for a quick insect snack but also jetting out into the air to snatch insects from the sky. They will eat a fair share of fruits too when in season. Summer Tanagers are specialized for eating bees and wasps, brazenly busting into hornet hives and ripping open wasp nests to eat their larvae or hawking bees on the wing for a honey-glazed meal. It’s not known whether they have any special resistance to bee and wasp venoms, or if they’re just fearless in the face of a free lunch.
Despite being an abundant, noisy, brightly colored, courageous killer of bees, Summer Tanagers are often hard to get good, close looks at. Like its other Cardinalid cousins, to include Grosbeaks and Buntings, they are curious but skittish creatures. Often they drop in to investigate neighborhood commotions, when Wrens and Titmice start sounding alarms, but will almost always dart out of sight if you turn your attention towards them.
