Common buckthorn Rhamnus cathartica
IDENTIFICATION — Growing quickly to a large shrub or small tree up to 20 ft. tall, common buckthorn has sharp spines at the tips of the twigs that can be dangerous as you walk through brushy areas. If you scratch the bark of this woody weed and it’s yellow underneath, you’ve found common buckthorn. Late in fall you’ll also notice that the foliage stays on this pest long after other leaves have fallen. And look closely at the leaves — there are usually three to five pairs of veins in each one.
FAVORITE CONDITIONS — Common buckthorn prefers places in part shade in moist to dry soil.
HOW IT SPREADS — Birds eat and spread the seeds of the 1/4-in.-diameter messy black fruit in fall.
CONTROL — When the plant is a seedling, pull or dig it out of the ground. If it’s too large for this, spray the plant with a nonselective herbicide, such as Roundup® Poison Ivy & Tough Brush Killer Plus in spring or late summer. Or cut down the tree and dribble or brush on a systemic stump killer around the edges where the sap is flowing. It’s absorbed into the wood and kills the roots. Be careful, it can kill any plant it gets on.