5. Sweetgum tree

In autumn the sweetgum tree looks beautiful. The worst part of the plant is its brown balls – they are spiny and come in thousands. The balls are harmful in more ways than one. You can slip and fall on them. Also, they can be shot out of a mower and injure you. It is not easy to rake the balls and the only way to get rid of them is to pick them up by hand. That’s a time-consuming and tedious task.