Tuesday, December 25, 2012
Corn Snakeroot - Eryngium aquaticum
Corn snakeroot (Eryngium aquaticum) is the most robust member of this carrot-family genus in Florida. Its distribution is rather scattered within the state; it is found in most of the counties that lie along the Gulf to west-central Florida, and in various other counties within that general latitude. It is not found south of the line from Manatee to Indian River Counties. It also occurs along the Gulf Coast from Mississippi and up the Eastern Seaboard to New York. Throughout this range, it is confined to wet sunny habitats such as freshwater marshes. There is some discrepency in the literature regarding its lifestyle - many report it to be a biennial (like many carrots), but my personal experience in Florida is that it behaves more like a short-lived perennial. Regardless, this is a species that does not persist long in the landscape even when given good growing conditions.
Corn snakeroot maintains a basal rosette of leaves through the winter in Florida. These leaves are grasslike, about 1/4 inch wide and up to 6 inches long. The margins do not have teeth or spines as they do in many other species in this genus.
Flower stalks emerge from the center of the rosette in early summer and reach their mature height of 2-3 feet by late summer. The stalks produce multiple branches near the top and a large rounded flower head is produced at the top of each. Like other species in this genus, each head is subtended by toothed bracts and each flower head appears spiny. What sets this species apart from others is that the heads are about 1/2 inch across and the flowers are normally a rich cornflower blue. Though a few other Eryngiums have blue flowers, their heads are tiny in comparison.
The flowers attract a wide variety of pollinators and maintain their showy appearance for several weeks. The foliage, however, is not used by the caterpillars of eastern black swallowtail butterflies though it is sometimes marketed that way. A few Eryngiums are useful larval plants for this butterfly, but corn snakeroot is not.
Because of its beauty, corn snakeroot is often grown commercially in Florida and made available to the home gardener. It is not an easy plant, however, to provide for. For one, it is not forgiving of droughty conditions. Over the years, a great many of my plants have succumbed to soils that have been allowed to dry out for more than just a few days. I have learned to keep it in spots that do not dry out and that stay wet to extremely moist during much of the year. It also does not survive long, even under optimum growing conditions. This is a plant that either needs to reseed to persist or be replanted every couple of years. I have not had great success getting it to reseed, so I purchase new plants from time to time. I find the effort worth the trouble because corn snake root, in flower, is a spectacular wildflower.