The Hills Are Alive

In Louisiana’s most botanically rich landscape, rare plants and ancient lineages persist in cool, shaded refuge

The Tunica Hills is a landscape treasured by many: photographers, birders, game hunters, botanists, herpetologists, ecologists, geologists, nature enthusiasts, and numerous others. It is a preternatural land of sheer bluffs, high ridges, steep slopes, and deep ravines—clothed by one of the richest upland hardwood forests in North America. When amongst these deeply incised loess bluff hills, with their ostensibly endless narrow ridges and deep ravines, you might feel like you’re in the heart of the Southern Appalachian Mountains—said mountains the only thing missing.

The Tunica Hills are found in West Feliciana Parish, Louisiana, and adjacent Mississippi. In Louisiana, this reach of hills is located primarily north of St. Francisville, west of U.S. Highway 61, and east of the Mississippi River bottom, occupying an area of over one hundred square miles, though these rugged blufflands extend well north into Mississippi.

The Hills derived their name from the Tunica (or Tunica-Biloxi) Indian Tribe, a Native American group that historically inhabited the Lower Mississippi River Valley.

Formation and Physical Character of The Hills

The physical character of these rugged hills formed over the last many thousands of years through deposition and erosion. The process began with the progressive deposition of wind-blown silt, called loess (pronounced “lurse” or “luss”), over millennia. Prevailing winds blowing primarily from west to east picked up silt from the adjacent Mississippi River Valley during times when river bottom soils were exposed after glacier melts; the most recent melting event occurred approximately ten thousand to eighteen thousand years ago. Eventually, these loess deposits accumulated to depths of up to fifty feet or more in places, on top of older geologic formations.

Over many thousand of years, these highly erodible loess soils have been worn and washed away by rainfall, and have thus been sculpted into a highly dissected wonderland of winding ridges.

These hills range in elevation from well over three hundred feet on the highest ridges, to a low of less than one hundred feet in the deepest ravines. Such is the degree of local dissection that the change in elevation can in places approach 150 feet from the top of the narrow ridge you’re standing on to the bottom of the deep ravine you’re looking down into. The distance between ridge tops is often no more than four hundred feet. Each ravine bottom supports its own intermittent creek channel that carries water after heavy rains, typically with sand, gravel, and clays revealed from the older geologic deposits below the brown loam loess. Amazingly, this sharp ridge-and-ravine landform repeats across an area of over one hundred square miles in Louisiana, broken only by a few larger streams, such as Tunica Bayou, Bayou Sara, and Little Bayou Sara.

Diversity in the Forest

Plant ecologist Dr. William Platt (now retired) and associates at LSU vouch that the forest that occupies these hills is one of the most species-rich of all Southern hardwood forests, particularly in the variety of woody species. The complex topography of these hills is filled with a variety of micro-climates and habitats. This is the result of the last ice age (the last glacial maximum, which occurred 26,500–19,000 years ago), during which a number of plant species more common to the north migrated southward, away from the advancing ice sheet, and found refugia in the deeply dissected ravine-lands of the Tunica Hills.

Scientists theorize that cold glacial meltwater and accompanying cool air masses moving down the Mississippi River combined with warmer Southern air to produce frequent foggy conditions, which provided abundant moisture and maintained cooler temperatures in the hills adjoining the river. Deep vertical ravines provided relatively cool, shaded habitat capable of supporting species intolerant of warmer and drier environments. Still today, relic populations of several of these northern species occur in the Tunica Hills, many at the southernmost extension of their range.

Historically, much of the forest was dominated by Southern magnolia, American beech, and American holly as indicated by General Land Office survey records from the 1800s. However, over the last two hundred years, and especially in the last century, the forest’s structure and composition have been altered by timber cutting and other human endeavors. While magnolia, beech, and holly are still present in abundance, they do not dominate as they once did, and large, old specimens are rarely seen. Extensive timber cutting has also favored the proliferation of faster growing trees in the Tunica—such as sweet gum, tulip tree, and cherrybark oak—and has set loose loblolly pine, a rapid colonizer of cutover land never seen in these hills until the forest alterations of the last century.

Despite these changes, conservation scientists believe the hardwood forests of the Tunica Hills still support the great majority of the plant and animal species that were present two hundred years ago.

Trees and Shrubs of the Tunica Hills

A number of notable native trees augment the remarkable diversity of the Tunica forest, owing principally to the rich soils found there. Many of these trees are attributed to the Florida Parishes, though they are almost exclusively found in the Tunica Hills region, including: Southern sugar maple, Carolina basswood, bitternut hickory, black walnut, Shumard oak, white ash, honey locust, cucumber magnolia, and slippery elm. The spectacular spring bloomer that is the redbud tree, a favorite landscape ornamental throughout the South, is native to these rich hills (and other areas in central and north Louisiana), but not so elsewhere in the Florida Parishes. Pyramid magnolia, a state-rare tree observed in less than ten locations in the state, is also occasionally encountered in the hills.

A variety of outstanding native shrubs are present as well, including mountain hydrangea, a shrub not found in Louisiana except in the Florida Parishes, where it grows most abundantly in the Tunica Hills. Its cousin, the oak-leaf hydrangea, is another uncommon Louisiana jewel, found on steep slopes throughout the Tunica region. Red buckeye, a relatively uncommon shrub in southeast Louisiana, has been seen to grow over thirty feet tall in these hills, truly gigantic specimens of a size rarely seen in the state.

Other beloved natives to the region that call the Tunica Hills their home include the common paw paw—which produces the largest edible fruit of any native woody plant in the U.S.— and giant cane, actually a woody grass also known as river cane. This versatile plant once gave rise to the region’s former name: the “Cane Hills.”  Historically very abundant, the grass was greatly diminished by cattle grazing in early settlement years.

Unique and Rare Flora of the Tunica Hills

The Tunica Hills are one of Louisiana’s premier botanical hotspots, supporting at least twenty-three known rare plant species per the Louisiana Wildlife Diversity Program (formerly the Louisiana Natural Heritage Program) of the Louisiana Department of Wildlife and Fisheries. Most of these are much more typical of areas north of Louisiana, such as the Southern Appalachian Mountains, but are found in refugia of the shady, deep ravines of the Tunica. (One additional species, American columbo, was recorded historically but is now presumed extinct in the region.)

Of these twenty-three species, five are known in Louisiana only to exist in the Tunica Hills, all being herbaceous ground story plants: white baneberry (or doll’s eyes), Canada wild ginger, silvery glade fern, Allegheny spurge, and American ginseng. The rarest of these is the American ginseng, known to exist in Louisiana in only one place, represented by a mere handful of plants in a small population deep in the Tunica Hills. Ginseng is an iconic plant of the Appalachian and Ozark mountains, and other areas of the eastern U.S. Amazingly, this small herb has been documented to have a life span approaching one hundred years.  It is arguably the most treasured of all wild native medicinal plants, with a wide range of reported health benefits. It is a plant so valuable, in fact, that it has been hunted to near extinction in many parts of its historic range due to the demand, primarily from Asian markets.  This has led to regulations on its collection in many states, in an effort to conserve wild populations.

Beyond the rarities, there are many other herbaceous plants noteworthy for their relative scarcity in the state or otherwise fetching features. Included in this group are Canada nettle, dutchman’s pipe, hound’s tongue, hone-wort, Southern stoneseed, and fetid wake-robin—a narrow endemic species found only in southeast Louisiana and southwest Mississippi.

One of the more interesting plants of the Tunica Hills is mayapple, also known as wild mandrake. It grows in sizable colonies, often consisting of only one or a few individuals that are spread by rhizomes. Each “plant” has only two leaves and one flower in the axil of the leaves. The large, umbrella-like leaves are showy and conspicuous, and flowers are solitary, nodding, and white- to rose-colored. The leaves, roots, and seeds are poisonous if ingested in large quantities, though the roots were historically used as a cathartic by Native Americans. The edible, ripe, golden-yellow fruits can be used in jellies.

One aspect of the native vegetation that is particularly striking in these hills is the abundance and variety of native ferns, which often form lush “fern gardens” over expansive areas. Some have called the Tunica Hills “the land of ferns,” home to more than twenty-five documented fern species, four of which are considered to be state-rare. One, the silvery glade fern, has been observed in Louisiana only in the Tunica Hills. Northern maiden-hair fern, a quite uncommon fern in the state, is another particularly eye-catching little dainty.

Unfortunately, there are also a few non-native invasive ferns found throughout the hills, the vilest of which is a new up-and-comer, Japanese lady fern.

Botanists and naturalists alike believe that undiscovered rarities perhaps still await in the Tunica Hills for the knowing eye. Private land and challenging access have hindered extensive floral exploration. Perhaps, though, we can see this as a blessing in the further conservation of these rare species and the complex ecosystems they call home. 

Rare Plants of the Tunica Hills

White Baneberry / Doll’s Eyes, Actaea pachypoda*

Canada Wild Ginger, Asarum canadense*

Low Erythrodes, Aspidogyne querceticola**

Carpenter’s Ground Cherry, Calliphysalis carpenteri**

Climbing Bittersweet, Celastrus scandens**

Fairy Wand, Chamaelirium luteum**

Enchanter’s Nightshade, Circaea canadensis**

Lowland Brittle Fern, Cystoperis protrusa **

Silvery Glade Fern, Deparia acrostichoides*

Deer-Tongue Witch Grass, Dichanthelium clandestinum**

Narrow Leaf Glade Fern, Diplaziopsis pycnocarpa **

Southern Shield Wood Fern, Dryopteris ludoviciana**

American Columbo, Frasera caroliniensis* (Historic)

American Alum Root, Heuchera americana**

Crested Coral Root, Hexalectris spicata**

Pyramid Magnolia, Magnolia pyramidata**

Snow Melanthera, Melanthera nivea**

Virginia Saxifrage, Micranthes virginiensis**

Allegheny Spurge, Pachysandra procumbens*

American Ginseng, Panax quinquefolius*

Shadow Witch Orchid, Ponthieva racemosa**

Maryland Black Snakeroot, Sanicula marilandica**

Bay Starvine, Schisandra glabra**

Nodding Pogonia, Triphora trianthophoros**

* In Louisiana found only in the Tunica Hills.

** Also found elsewhere in Louisiana.

One can interact with the beauty of these hills via various access points—the most famous being Clark Creek Natural Area in Woodville, Mississippi. This area is beloved by hikers due to its waterfalls, but can be quite crowded and trampled on weekends.

Another area of access, preferred often by naturalists due to its quieter, more secluded nature, can be found at the Tunica Wildlife Management Area—where one can find three separate trails off of Old Tunica Road. Old Tunica Road itself is a botanical joy, with stands of the rare Allegheny spurge, oakleaf hydrangea and other native plants scattered roadside.