The tree infests more than 234,000 acres in southeast Texas, according to Texas A&M AgriLife Extension’s Brush Busters guide . Many gardeners have planted something that has grown a lot faster than they expected. Take the Chinese tallow tree, which has heart-shaped leaves, bright fall foliage, and white seeds that resemble popcorn. People once thought its oily seeds might power a soap industry. The guide is meant to help landowners remove it. But how did a promising crop become one of the toughest weeds in the region?
The tree also starts producing seeds only three years after sprouting, and a single tree can produce up to 100,000 seeds, the review notes. The review also mentions fieldwork on the Texas coastal prairie showing that the canopy closed in 20 to 25 years. Another study it cites had the tree moving north through East Texas at just under 2 kilometers per year. Looking ahead, one model cited in the review predicted costs of $200 million to $400 million for the forest industry over 20 years of spread depending on how well the tree is controlled. Its herbicide methods were developed and tested by AgriLife professionals and should kill more than seven out of every 10 treated plants, but results can vary.
An expert advisory group has recommended releasing two biological control candidates, a flea beetle and a moth, the review notes, but neither had been released at the time of writing. Because removal is never a one-time job, the Texas guide says, the seeds are relatively long-lived, so landowners need to keep looking for new seedlings. The Texas A&M guide explains that the tallow tree is easy to establish, grows fast, and produces huge quantities of seed. The seeds are carried far from the parent tree by water and birds. Even cutting down the tree will not help in solving the problem, as it will regrow from the buds growing on its crown and roots. Thick stands of tallow shade the plants growing beneath them. The review’s authors consider the species one of the worst woody invaders, and it can take over both disturbed and untouched land. Its fallen leaves can also affect the breeding success of some frogs and toads that reproduce in winter . People also feel the impact. The Texas guide lists trouble in rice canals, irrigation systems, ditches, pastures, and fence lines. Control is possible, but it takes patience. Some beekeepers object, as the tree provides a rich nectar flow in the spring for bees. The tallow story reminds us how a handy plant in one place can become an expensive problem in another.
