READ THIS NEXT: If You Have This Tree in Your Yard, Cut It Down Now, Officials Warn. Invasive plants can do significant damage. Experts have issued warnings about other invasive trees, including the Bradford pear. While its decorative white blooms are a pretty sight to see, these trees can actually “choke out other plants,” according to USA Today. They also produce a rather unpleasant smell, which has been compared to dead fish and urine, and when they cross with other pear varieties, their offspring (called Callery pears) produce “thorns and thug-like thickets” that are sharp enough to puncture the tire of your car. Needless to say, if you have a Bradford pear tree in your yard, you should cut it down as soon as possible. Experts warn that other plant varieties like garlic mustard and poison hemlock should also be pulled on sight, but a different invasive tree makes this process a bit more difficult. Tree-of-heaven (also known as Ailanthus) is actually a misnomer, as this plant tends to be more demonic than angelic. According to the Nature Conservancy, this plant was first brought to the U.S. from China in the late 18th century. Similar to other invasive plants, this tree has no natural predators in the U.S. and has the ability to spread quickly. As North America and China have similar climates, tree-of-heaven has been successful at infiltrating 44 U.S. states, according to Charles van Rees, PhD, conservation scientist, naturalist, and founder of the Gulo in Nature blog. “You may encounter this plant, especially in urban areas, everywhere in the mainland U.S. except Montana, Wyoming, and the Dakotas,” van Rees tells Best Life. You can recognize this tree by its leaves. Van Rees explains that its individual leaves are long stalks “with a bunch of little leaf-looking things growing along it” placed on opposite sides. Also check for hair on the tree’s twigs, which are fuzzy and reddish-brown in color, as well as “tight clusters of little wind-dispersing seeds.” “The leaves of tree-of-heaven have sharp, lance-shaped leaflets, and they smell gross if you crush them,” van Rees said, adding that this is a good way to distinguish the tree from native species that it resembles, including the black walnut tree, various ash trees, and some varieties of sumac.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: For more up-to-date information, sign up for our daily newsletter. In addition to crowding other pants, tree-of-heaven weakens and kills other species by secreting chemicals into the soil, van Rees says, a process that is called allelopathy. “The aggressiveness and allelopathy of tree-of-heaven makes them extremely disruptive to existing vegetation, which disrupts habitat structure for other plant and animal species, and disrupts the food web by changing available food plants,” van Rees explains, adding that it also acts as a breeding ground for the spotted lanternfly, a harmful invasive insect. Making matters worse, tree-of-heaven does not only target other species—it also poses a threat to infrastructure, particularly concrete structures, and root growth can even damage pavement and plumbing. “This is particularly problematic because it can live just about anywhere, even in poor-quality soils, and in all kinds of shaded or sunny environments,” van Rees says. “Besides its impacts on native ecosystems and species, the Ailanthus has a pretty ugly smell to it, so it’s a bit of a pest.” According to van Rees, there are different ways to tackle a tree-of-heaven problem, depending on what stage of life the plant is in. When it’s young, the tree can be pulled out of the ground, but if you’re dealing with an older tree, the process becomes more complex. This is thanks to a “strong and thick” taproot that the plant grows deep into the soil, which makes pulling difficult and sometimes requires mechanical removal. “People usually resort to cutting down the plant at this point, but this is unlikely to kill the plant, which can spread through its roots (called suckers in this case) underground,” van Rees says. “To ensure that it is killed, some people will cut all of the above-ground trunks or stalk, then drip some herbicide right onto the cut stem so that it gets into the vascular tissue and then into the root. This can stress and kill the plant.” Van Rees explains that this is a better approach than just spreading herbicide, which can actually kill plants in the surrounding area. However, he adds that some experts recommend yet another approach. “Plant pest control experts at Pennsylvania State University Extension recommend treating the roots of well-established plants with specific herbicides, waiting until late summer or early fall to apply them at the right time,” he says. “For homeowners, the simpler ‘hack and squirt’ method may be best, where you cut a notch in the stem of the plan and apply herbicide to the wound so it enters the vascular tissue.”
