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Sunday - July 24, 2011

From: Austin, TX
Region: Southwest
Topic: Invasive Plants
Title: Root barriers for invasive plant roots from neighbor in Austin
Answered by: Barbara Medford


My neighbor's invasive plantings are invading my yard. He has Chinese parasol, China berry, Japanese honeysuckle, privets, ligustrums and native Mustang grape vines planted so closely together they are fighting for water and light. The vines are on his fence and the trunks of the trees and shrubs actually touch it; many are within 10' of my house. They suck up the water I use on my native shrubs and in this drought I am watching every drop I use. I fear some root will undermine my foundation as it searches for more water. He won't remove any of the plantings. He does water, but I continue to find and fight the root suckers or baby plants that have managed to erupt through the caliche at least 40' from the adult plants. Another more tactful neighbor made suggestions about thinning the plantings to relieve their stress, but that fell on deaf ears. I've contemplated trenching along my side of the the property line and installing a root barrier right next to his fence. Will that stop the invasions? Any suggestions?


You have several major problems, as we are sure you know, and not much of any way of solving them with plants, which is what Mr. Smarty Plants tries to do. Of course, if gardeners all listened to Mr. Smarty Plants in the beginning, there would be no non-native invasives such as Firmiana simplex (Chinese Parasol), Melia azedarach (Chinaberry), Lonicera japonica (Japanese honeysuckle), or Ligustrum japonicum ( privet) being planted in the Austin area, but obviously there are. Each link above will take you to a website that tells why these plants are so undesirable.

You are probably not going to be able to convince your neighbor to control or remove his invasive plants. Even if the homeowner went out today and cut down all the alien invasives, their seeds and roots would perpetuate their existence. We did a little research on Root Barrier instructions, most of which were advertisements, but this one seems to have some good advice.

About all you can do is fight a defensive action. Putting down a root barrier on your property line, cutting off any roots coming onto your property and perhaps painting the stubs with an herbicide might slow down the progress of those roots. If you choose the cutting and herbicide route, use an undiluted solution and a small disposable sponge paintbrush, painting the cut surface immediately so the herbicide will be absorbed before the root starts healing over to protect itself. This is not going to be sufficient to kill the neighbor's tree, but might keep that particular root from regenerating into your space. When you have dug out a trench and treated such roots as you can, then you can get the root barrier in. We have no personal experience with this, so you might want to get professional help.

Beyond that physical barrier, you will have to be vigilant about suckers and seedlings in your garden, removing them by pulling, cutting or mowing as quickly as possible. Our hope is that other gardeners planning their landscaping will read this and understand the damage they can do to the environment and to neighborhood relations by putting in plants that are non-native, invasive and totally undesirable. You and other interested gardeners should read our How-To Article When is a Guest a Pest? The best way to control invasive plants is to never plant them.


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