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MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

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Oct 06

Pest … or Welcome Guest?

Posted on October 6, 2017 at 10:52 AM by Ann Vallee

by Charlene Burgi

Nobody likes a pest—at least nobody that I ever met. Garden pests can come in a variety of forms including insects, deer, rabbits, squirrels and, of course, weeds. What counts as a pest can vary from place to place. A plant that is well behaved in one climate or location may become a problem in another. 

Invasive plants can cause many types of problems in our gardens. For starters, they sap the water and nutrients that our other plants need to stay happy and healthy. Worse yet, they can take over an area if left to their own devices, choking out the wanted plants. 

Sometimes pests are brought into our garden by our own hands. This includes invasive plants that we unknowingly purchase or acquire from a well-meaning friend. Many years ago, such a friend thought to fill a newly built raised planter box in my backyard while I was on vacation. Unfortunately, this gift also included the roots of an invasive bulb that proved a challenge to eradicate.

 Baneberry (Actaea rubra)
Do you have a plant that just appeared in your garden and isn't familiar to you? It could have arrived as a seed on the wind or dropped from a bird flying by, or carried in on a purchased plant. In fact, this past weekend I found a beautiful berry-bearing plant growing along the creek. The plant was unfamiliar to me and the need to know brought me to one of my favorite online resources: Did you know you can key unknown plants on the CalFlora website? This website includes photos to help confirm identifications. Check it out, as it can help with early detection of pests, as well as general identification. You might just find the mystery plant is a winner. In this case, I discovered the plant to be baneberry (Actaea rubra), a toxic plant that thrives in wet, shady areas of a garden. I then double-checked if it is invasive using another great resource, the California Invasive Plant Council (Cal-IPC) website. Good news: Baneberry didn't fall into that category. This pretty thing is a keeper.

Pest plants are a broad topic—books have been written on the subject. Yet the definition that stands out best for me is: A weed is any plant growing where it’s unwanted. That definition was an eye opener to this gardener. Just be wary of the wanted plants that can escape and become unwanted invaders in other areas!


Anonymous User
October 6, 2017 at 6:30 PM
Did you get my last communication? ...about invasive spearmint and rats that are eating my tender plants! Do I have to stop composting after 45 years. Would like to get a live animal trap!! Susan Mc conneloug
Anonymous User
October 11, 2017 at 8:41 AM
Susan, I am sorry to say I did not get your inquiry. Your brief list of issues befits the perils of gardening! Spearmint is invasive as you well know. The organic means of eliminating it requires due diligence on your part. Dig up as much as you can. Understand it is one of those plants that will continue trying to come back up if the tiniest root is left. The first sign of reemerging requires more digging. You can also try covering the area with black plastic over the summer after digging to see if that would "cook" the roots. Capturing any animal live requires, by law, for you to dispose of it in a humane manner. To my understanding, captured animals are not to be released elsewhere and pose pest problems for others. Best check with your local laws about that one. As for composting over 45 years - Good for you!!! Stop if you have the need to stop or offer that rich compost to a lucky neighbor or friend! Again, sorry for the delay. Sincerely, Charlene .

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