Hackberry

No, I was thinking of something different. Years ago on her show, Rebbecca Kohl's mentioned an invasive tree that is on the list of trees that should be removed from any landscape. By her description I knew I had scads of them on my two acres. We attempted to get rid of all of ours. Unfortunately our neighbors all have them and the birds easily spread them around. Hackberry was not the name she used. The berries are black, the leaves are round dk green and look dirty or scarred all the time.

Buckthorn?

I don't know about the "dirty or scarred" leaves but it does sound like buckthorn. Rhamnus cathartica or common buckthorn is the one we have everyplace where I live.

FataMorgana

I have buckthorn to be sure. My mind is leaving me. Maybe they are on in the same. I just know I was watching a garden show and they showed this tree and urged everyone to remove it from any place it was found. We had been removing many prickly trees Prickly Ash and others brush. When this one was shown we went after it too. Who knows, maybe my daughters leaf project will solve the mystery.

Just found a site to look at pictures. Buckthorn it is. Buckthorn and prickly ash, what a mess I have!!

Well, THe prickly ash is irritating and you wouldn't want it in any place you plan to walk through the brush, but at least it is native, which means it isn't a threat to the ecosystem, and it supports native insects and wildlife. Birds, including some birds which are primarily insect eaters, eat the small fruits on prickly ash. I guess that probably doesn't give you much comfort while you're hacking away at a big, thorny prickly ash, but thought I'd mention it anyway.