Okay, this is a little different, but many Central Texas gardeners wind up with these vigorous seedlings. This winter, Lindsey Heron had an old hackberry tree cut down. In spring, the area was covered with tiny seedlings. Many of these could actually be “root suckers.”
Hackberries are prolific re-seeders and prone to suckering. The best thing to do is to pull them out while they are as small as possible. Moist soil makes this a lot easier, so irrigate the area the day before. Be sure to dig down below the seedling to loosen the soil, which will make it easier to get as much of the plant as possible.
Even still, the seedlings may break when you tug on them. If this is the case, watch for the plant to regrow, then try again. You can also cut the seedlings each time they re-sprout, or even mow them, if you’re able to. Sugar hackberries do not give up easily, so you’ll need to keep fighting them until you finally win. This process may take years!