As part of our plan to understand dune succession, we’re looking at Sea Rocket. This salt-resistant (and tasty) dune colonizer is a sign that more plants are probably to come.
Sea Rocket, Cakile edentula harperi, is a succulent, shrubby plant that is one of the first plants to colonize a dune. It has waxy leaves that can store water: if it has been raining recently, the leaves are thick and solid. In drier times, the water is used by the plant and the leaves are thinner. The seedlings grow early and fast enough that a plant can produce mature plants, flowers and seeds all in the same season. We see these four-petaled flowers in the spring.
Part of the Brassica family
As a member of the mustard, kale, and cabbage family, this plant is edible, with a salty punch. While we were looking at Falcate Orangetip butterflies last week, I came across a small caterpillar under a sea rocket, and wondered if this might be one of the host plants for that butterfly. I’m still looking around for other brassica species that might serve the same purpose.
As an early dune colonizer, the structure of the p;ant catches sand which can build the dunes. It also provides habitat for all kinds of shorebirds like this Wilson’s Plover.
One of the interesting things about sea rocket is the double lobed fruit. There are two halves of each fruit: on is buoyant and breaks off, floating on the tide to new horizons. One drops off and reseeds the area where the plant is!
I’m always glad to see it on the beach– as we face higher tides, some areas of our beach are eroding and some are accreting. Something about the rows of sea rocket reminds me to take it in stride and watch for new growth.
Sea Rocket creates Dune Habitat
Check out this photo of a ghost crab and Wilson’s Plover stand-off. The sea rocket provides cover for these beach residents to be inconspicuous.
