Pennyworts (Hydrocotyle spp.) are distinctive plants with long, trailing stems and leaves resembling small lily pads with scalloped edges.
Each leaf is attached to the main stem via a long stalk arising from near the center of the leaf.
The name “pennywort” comes from the circular shape of the leaves and from an old English word (“wyrt”) meaning “plant.”
Pennyworts are in the same plant family as English ivy and ginseng, and worldwide there are some 75 to 100 species. A few are cultivated as ornamental aquatic plants.
One common South Carolina Lowcountry species is beach pennywort (Hydrocotyle bonariensis), which you’ve probably seen creeping across Lowcountry dunes via meandering rhizomes that are mostly buried beneath the sand.
During the summer, the plant produces clusters of small white flowers and dry, flattened fruits.
Beach pennywort grows along the south Atlantic and Gulf coasts, where it’s well adapted to the harsh conditions faced by dune vegetation, such as bright sunlight, high surface temperatures, and low nutrient levels. Its tough, fleshy leaves and stems stand up to blowing sand and salt spray and help protect against moisture loss.
The plant’s prostrate growth habit shelters it against strong winds. And its trailing stems, sometimes 10 feet or longer, help propagate the plant across shifting sands.
In fact, mats of spreading beach pennywort help colonize and stabilize our Lowcountry dunes.
Other species, such as marsh pennywort (H. verticillata) and many-flower marsh pennywort (H. umbellata) thrive along the edges of lagoons, marshes, and other wet areas.
Sometimes they invade moist lawns and are regarded as weeds, though they can make a good, deer-resistant ground cover in just the right spot.
The leaves of some pennyworts are reported to be edible raw or cooked as greens. However, caution is advised, since ingesting the leaves may cause nausea, particularly in the case of pennyworts growing in places that have been treated with herbicides or other chemicals.