Nandina: A Berry Interesting Problem

Oh, nandina, nandina, you trouble my heart!  You are so beautiful all winter with your green foliage and bright red berries, but you are an invasive plant.  What is a good naturalist to do?

Nandina, AKA heavenly bamboo.

Invasive species (species = type of organism) are a problem in Tennessee, and in the rest of the world as well.  They are currently the #2 cause of extinction of other species, just after habitat destruction.   Invasive species are non-native organisms that grow like crazy and take over.  Non-native organisms are moved from one part of the world to another, mostly by humans.  This is usually not a problem, except that for some non-native species, the new habitat has none of their usual diseases and predators, and the habitat seems to fit just right.  In that case....they can take over and crowd out the habitat of other organisms.  Nandina is native in Asia - from Japan west to India.  It is a beloved plant there, also used in landscaping like we use it here. 

Poisonous beauty: these berries contain nandina seeds and cyanide!

In Tennessee, some of our most harmful invasives are bush honeysuckle and kudzu.  Bush honeysuckle uses up habitat for other plants.  Also, birds that nest in it are more likely to get eaten (not sure why).  Kudzu simply crowds out every living organism where it grows.  Nandina is not that bad!  It is usually only found growing wild near where humans have intentionally planted it.  The Tennessee organization that helps keep invasive plants under control (TN-EPPC)  wants more information about nandina in order to keep tabs on the problem.  If you are ever out hiking in the wild (not in a landscaped yard) and you see a nandina, TN-EPPC would like to know about it.  You can report an escaped nandina at the TN-EPPC website: http://www.tneppc.org/

A nandina draws your gaze from behind a sedimentary rock.

Biologists worry about invasive species because they cause the total number of species to decrease.  The loss of a species, or extinction, causes the loss of a participant in an ecosystem.  For example, when a bird species dies out, an ecosystem might lose a seed-disperser.  If honeybees died out, there would be way fewer pollinators and thus way fewer fruits and seeds.  If a type of beetle died out, we might lose a soil recycler. 

Nandina is guilty of taking up a tiny bit habitat that would otherwise be used by native species, though it doesn't appear extremely aggressive.  It has another problem, though.  Nandina berries contain a toxin called cyanide.  Birds in the US haven't figured out how to deal with the poison, and some cedar waxwing birds have died from eating lots of the berries.  The berries can be toxic to any other animal too, so don't eat them. (It probably takes a lot of berries to hurt a large animal such as a human...still...don't eat them.)

Back to the original question: what's a good naturalist to do?  That depends on who you ask.  Some will say to never plant nandinas.  Others say plant them but clip off the berries this time of year when birds start foraging.  Others say don't worry about it - eventually the other species will adapt and nandina will become another important part of our ecosystem.  The only problem with this last option is that adaptation takes hundreds to thousands of years, so we won't find out how nandinas mesh with our Middle Tenneessee ecosystem for a looooonnnngggg time!  What do you think we should do?