Description
Alisma subcordatum | American Water Plantain
American Water Plantain, also called Mud Plantain and Southern Water Plantain has a native range from Massachusetts to Minnesota, and south to Florida and Texas. It’s an herbaceous perennial that, as an emergent aquatic plant, has its base and lower plant parts, including its ribbon-like leaves below the water’s surface, while the upper, more broad-leaved foliage is exposed and floats above the water. Independent, single or multiple branched stalks rise from the plant base up to a height of 3 feet, displaying cute and dainty white or blush-pink three-petaled flowers that bloom from June to September. The miniature flowers are a useful nectar source for some beetles, flies, Halictid bees, and other small insects.
This broadleaf emergent plant can be found growing in shallow, quiet to slow moving water, and in mud of marshes, lake margins, ponds, streams, ditches, and seeps. It’s also useful for ditch planting as it tolerates fluctuating water levels, this also makes it ideal for use in SUDS (Sustainable Urban Drainage System) planting scheme. It requires organic or silty soils, with seasonally or permanently inundated freshwater. To grow optimally, it requires full sunlight.
Plants are remarkably hardy, well-adapted, and loves to have its roots wet, Alisma subcordatum is most commonly found all along riverbanks, lakes, and ponds. With a combination of tubers and rhizomatous roots, American water plantain is excellent at filtering water and has been utilized throughout the U.S. to help clean up and restore wetlands and water retention ponds. In addition, it provides nesting and resting spots for helpful macroinvertebrates like caddisflies and alder flies, which in turn provide a valuable food source for fish, turtles, newts, and waterfowl.
Despite having rhizomatous roots, water plantain doesn’t spread too quickly and as such, is unlikely to overtake your pond. Over several years time though, colonies can form. This is usually a slow process, which can be remedied quickly, if needed.
American Water Plantain is edible and is often eaten by waterfowl, deer, wild fish species like trout and bass, plus turtles and newts. Some pond fish, like Koi, may nibble on roots and leaves, but likely not enough to damage the plant beyond repair, nor will the plant harm your fish if consumed. People can also eat the roots, which are quite high in nutrients and useful carbohydrates.
In the wild, American Water Plantain seeds easily on its own, with the seeds overwintering. Seedlings will emerge on exposed soils, in stands of existing vegetation, or in newly disturbed locations. However, to grow from seed you will have to break their natural dormancy giving them a period of cold-moist stratification by refrigerating damp seeds (in soil) for several weeks, and then planting them. Sometimes it’s easier to just let nature take its course and sow seeds outdoors in fall or winter, or even placing them beneath fallen snow to germinate naturally during the coming spring.
Type: Aquatic perennial
Water planting depth: 4-12 inches
Sun exposure: Full sun to part shade
Mature height: 12-36 inches
Mature width: 12-18 inches
Perennial zones: 4-9
