Welcome to my first blog post on invasive plants in southern California. If you would like to get a better idea of my background and work, please visit my website at http://ucanr.org/sites/socalinvasives/.
I have been planning to start this blog for at least a couple of years, but kept waiting until I had plenty of free time to get it going and keep it going. Well, that time has never arrived (go figure) so I thought I had better start now. I am also thinking about retiring and want to get as much of what I know about weeds out of my head and computer files to an accessible place for people that might find it useful. This first blog is about my philosophy of weed management, in the sense that a philosophy can help you create an effective strategy for managing invasive plants.
1. It’s the habitat, not the weed.
I heard my friend and colleague John Randall (ecologist with The Nature Conservancy) repeat this key concept several times at annual meetings of the California Invasive Plant Council. I also learned it in the field working with farmers on weed problems in the Imperial Valley.
It doesn’t matter what the non-native, exotic, or unwanted plant species are that are invading your site; in order to restore the habitat they all have to go, or at least be reduced to an insignificant problem. Focusing all of your effort and resources on killing one species, even problem ones like arundo, artichoke thistle, fennel, pepperweed, starthistle, onionweed or whatever and ignoring everything else won’t make the habitat better.
2. Its gonna be a long ride. One year of treatment is never enough. If you are not prepared for a multiyear effort, don’t waste your time and resources. In my research I have seen pretty significant results by year 3, but I still don’t know when that year is that I can say, “Done, its all better now.”
3. Be prepared for surprises. The seed bank in your site has lots of surprises in store for you; you’ll see weeds that you were not expecting. You’ll wonder how they got there because you have never seen them before. They got there the usual way, someone brought them in long ago, they’ve just been hidden beneath the more aggressive species like the annual grasses.
4. Learn how to do it right.
One time I was walking around a small restoration site near the mouth of the San Diego River. It was June and there were piles of dead weeds in between bare shoots of willow. So whoever was in charge decided that they would plant willow slips in spring, then at the end of the rainy season, they would mow the weeds. This is revenge, not weed management! The weeds were already senescing, they had sucked up all of the winter’s rainfall, they had produced thousands of seed; the willows were barely alive and would spend the summer in drought, and the weeds would be back with the first rain to start the cycle over again. Not a formula for success, but I bet it felt satisfying to get rid of all those weeds.
Thanks for reading this post, there are more to come. I would greatly appreciate your comments, questions and suggestions for topics (of an appropriate and relevant nature; I reserve the right to decide what is posted on this blog); this will be the most fun for me if it is interactive and conversational. You can email me or follow me on Twitter (who says an old dog can’t learn new tricks).