Little Green Leafy Clumps On Leafless Trees During Winter

Q: What are the little green leaf clumps visible in winter in leafless trees?

A: I believe you’re seeing clumps of mistletoe. This small, evergreen shrub is seen most often high in the branches of bare pecan, hickory, oaks, red maple, and black gum trees. Mistletoe sends out root-like structures into tree branches, from which it steals water and nutrients. It is semi-parasitic: it derives much nutrition from the host tree’s sap but it manufactures some of its own food too. When birds feed on mistletoe berries, the seed inside the berry passes through the bird’s gut surrounded by a sticky film that helps the seed stick to tree branches when it comes out the other end.

Areas, where trees are heavily infested with mistletoe, are often indicative of a healthy bird population. Mistletoe spreads and grows relatively slowly and is rarely an immediate threat to tree health. Healthy trees are able to tolerate a few mistletoe plants with little harmful effect.