They have clusters of white flowers in late spring followed by bunches of black-colored berries. The most effective method of removal is to dig out the roots, because even tiny stumps left by hoeing will sprout. I have cut a few branches from a tree that grows in a neighbor's yard. I was wondering if you could identify the tree. Birds are crazy for the berries, but they don't manage to eat all of them.
Leftovers fall to the ground and create a sticky mess.
A friend thought maybe this was a jujube tree. The fruit often is used for jam and wine. Let us hear from you.