I have this viney, thorny plant in my backyard
that takes over everything. I would like to find out
what it is. I’ve tried pulling it out and using roundup but nothing works.
this is a difficult one. My best guess is that this is a young stem of Cudrania tricuspidata, sometimes called Mandarin melon berry. These are probably root sprouts from a large underground stem, and it is probable that this tree was planted a long time ago when it was more popular. It is related to the mulberry. Also, the plants are dioecious – either male or female. They are also related to the Osage orange.
Dr. Steven Hill, Botanist, SCNPS