Smilax Berries: Bird Food That Spreads a Thorny, Invasive Vine

Q: On a woods walk I found black clusters of berries. What are they?

They're a fine bird breakfast, but one I wish they wouldn't eat! Berries are seeds of the thorny, noxious smilax vine. Glossy green leaves are attractive but it's a miserable weed.

I clip smilax vines to the ground every chance. If I have energy, I dig up yellow roots.

This is the only way, other than persistent glyphosate spraying (click for sources), to eliminate this menace.

I hope you'll retrace steps and damage the vine.