Many of the plants in the sand dunes are dormant through the winter months but are now just starting to wake up. We will start our #dunebloom series with sea rocket (Cakile edentula), one of the first green plants you’ll see popping up on the sand dunes in the late winter/ early spring. A member of the Brassicaceae family, sea rocket is a cousin to broccoli and radishes and exhibits the four-petaled flowers typical of this plant family. It tolerates the harsh conditions of the beach in several ways:
1) Just like a cactus in the desert, the succulent/fleshy leaves of sea rockets help it to store water in the dry environment of the sandy dunes.
2) The plant also protects its investment by producing and storing bad-tasting toxins, called glycosylates, in its tissues. These chemicals help to protect the plant from hungry caterpillars and other herbivores that would strip it of its leaves as they search for food in this barren environment. (Incidentally, glycosylates are the reason that some people do not like to eat broccoli!)
3) After it blooms, each sea rocket flower produces an unusual pair of fruits. One fruit stays attached to the mother plant to germinate in what was a successful location for her, but the other can detach and float to another location; a successful bet-hedging strategy in this unpredictable, erosion-prone environment.
These traits serve sea rocket so well, that it has a remarkable range, occurring along the Atlantic and Pacific coasts of the U.S. and Canada as well as the freshwater beaches of the Great Lakes. All dune plants play an important role in holding the sand in place with their roots and trapping sand as it blows across the beach. Enjoy observing these #duneblooms, but be sure to leave them in place so they can do the important work of protecting and building our beaches!