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Ask the Master Gardener: Chinese Tallows have nice fall color but are invasive to wetlands

By: Gay Wilhelm Placer County Master Gardener
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Question: I have a Chinese Tallow tree in my front yard near a walkway. I’m told it should come out because of shallow roots and that it’s an invasive tree. Is this true? Answer: Sapium sibiferum, Chinese Tallow, is a deciduous tree that grows up to 40 feet. Characteristics that make this tree a popular ornamental are its fast growth rate, attractive fall color and its ability to resist damage from pests. Chinese Tallows normally have strong, deep taproots. This enables young trees to withstand periods of drought. But when planted near a lawn, the roots may grow toward that more frequently watered area, thus becoming shallow rooted. But to the more important question, is it invasive? Yes. It is now known to be a prolific invader, capable of overtaking wildland areas and rapidly replacing native species. You will find them in the wild adjacent to streams, in coastal areas and along roadsides. Chinese Tallow produces abundant seed at an early age. The seed is spread by birds and can float for long distances in wetlands. Once established it is very difficult to eradicate. Flooding isn’t effective. It is toxic to cattle so grazing isn’t possible. (Note: the leaves and fruit also cause vomiting in humans.) Biocontrols are not available. Cutting does not help since plants resprout vigorously from the roots. Burning during the dormant season may be effective but not always practical. Numerous trees have been found among native vegetation along the American River Parkway. Closer to home, there are reports of tallows along streams in Placer County. It may be wise to remove your tree especially if you are near wetlands. If the tree is too mature to easily remove its roots, cut it down with a chain saw. The final cut should be made as close to the ground as possible and as level as possible. This will make an herbicide application easier Seedlings should be continually pulled by hand before they reach seed-bearing maturity. And remember to consider other trees before planting this serious invader. Have gardening questions? Call the Master Gardener Hotline at (530) 889-7388.