So, is it Noxious, Poisonous, or Simply Obnoxious?

Since I am waiting for some samples using barriers to be done, I thought it might be a good time (or as good a time as any) to start a series of short articles about poisonous plants. What is too poisonous to use? What defines poisonous or noxious? This comes up because of some rather odd conversations I have had recently and a plant list I pulled off the internet (it was pretty confusing, even to a plant geek like me).

So, let's figure out what we are talking about first. When you search the word noxious for a dictionary definition here is what you get:

"Noxious: harmful, poisonous, or very unpleasant."

The definition of the phrase "noxious weed" is a bit different and I think it is important to know the difference; not only for the purposes of what is ok to eco print with, but more importantly, what not to plant in your garden. It is estimated that half of any list for any given area are plants that started out as intentional plantings. I found this definition on the Skamania County Washington Weed Board site and it seemed to be the most succinct:

"'Noxious weed' is the traditional legal term for an invasive, non-native plant that threatens agricultural crops, local ecosystems, or fish and wildlife habitat. The term includes all nonnative grasses, flowering plants, shrubs and trees. It also includes aquatic plants that invade wetlands, lakes, rivers and shorelines. Noxious weeds cause damage that has considerable environmental and economic costs."   

Note that it does not say that all noxious weeds are poisonous, although some are, if not to humans, then to livestock and possibly wild animals. By the same token, many native, naturally occurring plants are poisonous, so they are unlikely to make it on to a noxious weed list. For your own safety it is important to know what they look like and where you are most likely to come across them. Poison ivy comes to mind, it is poisonous to almost everyone and the rash you get is truly obnoxious; but unless a given environment is really out of balance, it rarely appears on a noxious weed list. You will be happy to know that this is one we sent other places, in the 1800's it actually got drug back to Europe as a garden plant where it escaped into the environment.

Invasive thistles qualify as noxious in every sense of the word; they are harmful and unpleasant as well as being invasive. But, believe it or not, most true thistles are edible at least when young. You have to wonder how hungry somebody had to be in order to try it out.