Tuesday, November 25, 2008

Nandina domestica

Nandina domestica, unfortunately, has gorgeous fall color this time of year:

I say it's unfortunate because in the past ten years or so it's become apparent that this plant is fairly invasive in the southeast US. I suppose it is not a total surprise, as this plant is in the Berberidaceae family, which also includes Berberis thunbergii, the Japanese barberry, which is also highly invasive.

When I teach students about invasive plants like barberry and nandina, I try to instill some sense of responsibility in them. While I personally am not outraged by the use of these plants in intensely urban conditions (where they will have a very hard time finding nearby woods to invade), one should seriously consider alternatives when they live in suburban or rural areas, as no doubt such species will misplace the native herbaceous and shrub layer of forests and meadows.

The plant above is growing in my parents place in Virginia. They have a wooded lot, so while we haven't removed it, we do check out the woods and remove any would-be conquerers.

Many feel that native plants should be exclusively used in order to prevent invasion of plants like nandina and barberry into nearby natural habitats. It's an ongoing debate. While I avoid using invasive plants, I don't eschew all exotic species, though some may consider it more politically correct.

I've begun reading the Robert Sullivan book, Rats: Observations on the History and Habitat of the City's Most Unwanted Inhabitants. Coincidentally enough, last night I read an interesting description of the native/non-native debate in a footnote I've copied below. It doesn't address the subtle, vital difference between non-native and invasive, but it did include some new information:
The term native when used in regards to plants and animals can be complicated. In an essay entitled "The Mania for Native Plants in Nazi Germany," published in a collection called Concrete Jungle, Joachim Wolschke-Bulmahn, the director of Studies in Landscape Architecture at Dumbarton Oaks, in Washington , D.C., says, "The missionary zeal with which so-called foreign plants are condemned as aggressive is significant. Such characterizations do not contribute to a rational discussion about the future development of our natural and cultural environment, but possibly promote xenophobia." Wolschke-Bulmahn points out that some plants that are considered "native" to the United States may have been carried over from Siberia by people migrating to American over a land bridge, and he writes of an early proponent of native plants, Jens Jensen, a landscape architect who lived in Wisconsin who advocated the destruction of "foreign" plants, especially "Latin" or "Oriental" plants. Jensen had close ties to Nazi landscape architects in Germany. In a journal, Jensen wrote: "The gardens I have created myself...shall express a spirit of American and therefore shall be free of foreign character as far as possible." In 1938, Rudolph Borchardt, a Jewish writer persecuted by the Nazis, wrote this of native plant advocates like Jensen: "If this kind of garden-owning barbarian became the rule, then neither a gillyflower nor a rosemary, neither a peach-tree nor a myrtle sapling nor a tea-rose would ever have crossed the Alps. Gardens connect people, time and latitudes...The garden of humanity is a huge democracy. It is not the only democracy which such clumsy advocates threaten to dehumanize."
The book, by the way, is a terrific read, not only full of fascinating, at times squeamish, information about rats but also about New York City history. It reads very easily, too.