This week for Flora and Fauna Friday, we have our state tree to discuss. This week we’re talking about Palmettos, genus Sabal.
Here on Edisto Island we have two species of Palmetto, the Cabbage Palmetto (Sabal palmetto) and the Dwarf Palmetto (Sabal minor). The plant that’s on our state flag and found across our barrier islands, maritime forests, and parking lots is the more “tree-like” Cabbage Palmetto. A smaller species known as Dwarf Palmetto can also be found here in dense stands through the swamps and floodplain forests. This species rarely produces a visible stem. Young Cabbage Palmettos and full grown Dwarf Palmettos can often be hard to tell apart but there’s a simple trick to do so. The fresh fronds of Cabbage Palmettos produce strings between the segments of the leaf and Dwarf Palmettos do not. Additionally, Dwarf Palmettos are partial to forested wetlands and Cabbage Palmettos prefer barrier Islands and maritime forests. I’ll be talking about Cabbage Palmettos for the most part today.
Cabbage Palmetto is typically a small tree but can reach 30ft in height in ideal conditions. It has a straight fibrous trunk topped with a spherical crown of fronds. Each frond is a single leaf with a divided, circular, fan-like blade. The blade of the frond is connected to the trunk by a woody petiole that forks at the base. As the frond ages and is senesced, the blade breaks off. This leaves behind the forked base, called a “boot.” These boots can stay attached to the trunk for decades or may be shed after only a few years. Our Palmettos flower in late spring, producing a massive flower stalk covered in hundreds of small, cream-white flowers that are irresistible to bees and wasps. Come summer, their fruits, small black drupes, mature and are devoured by Mockingbirds and Raccoons.
Palmettos, like other Palms, are not true trees. They are monocots, just like Grasses, Orchids, Sedges, Lilies, and Onions. As such, Palmettos cannot grow laterally, only vertically. A true tree, like a Pine or Oak, will grow both taller and wider over time and produce a stem made of dense wood. Palms can only grow taller and their stem is a dense column of fibers instead of wood. They also produce a tangled ball of thin roots beneath their trunk rather than the elaborate branching root system of a woody plant. This is because a Palmetto tree only has one massive bud at the top of the plant, from which all leaves are produced. The trunk, which grows one layer at a time, can only be as wide as that one bud. This bud is an edible vegetable called “heart of palm” or “swamp cabbage” but removing this bud will kill the entire tree. So I can’t recommend foraging for it. This peculiar biology of Palm trunks allows the Palmetto to store months’ worth of water inside itself and makes it practically immune to hurricane force winds. The fibrous logs of the Palmetto earned it its place on our state flag. During the Revolutionary War, Fort Moultrie on Sullivan’s Island was critical to the defense of Charleston Harbor. The Fort was able to survive bombardment from the British Navy because it was constructed of Palmetto logs and loose sand. Traditional wooden and tabby fortifications would shatter and crumble under the force. The fibrous logs flexed and absorbed the impacts of the cannonballs, like a natural Kevlar vest.
