This time of year is usually when we think about mistletoe as we see it used in Christmas decorations, hanging over the doorway, as a way to steal a kiss, etc. Unfortunately, that is all the pleasurable thoughts we can have about mistletoe because it is a bad parasite for trees. The mistletoe is growing in the trees year around but it stands out this time of year because of the lack of leaves on the trees.
A parasite is an organism that derives its survival from another living entity, and in this case, mistletoe is the parasite and trees are the living entity on which it must survive. In this area we see most of the mistletoe on American elm, cedar elm, hackberry and blackjack oak. For some reason, these trees seem to be easy hosts for mistletoe to grow in. Mistletoe is dependent on the host tree for all water and dissolved minerals. It is however, a chlorophyll containing plant, which manufactures the sugars and starches needed in its growth and development.
Mistletoe stems bear conspicuous green, leathery leaves which persist for several seasons. Nutrients and water are supplied from an absorbing system which develops in the bark and wood of the host tree. Flowers are born in the leaf axil and produce the familiar, nearly clear, whitish berries in late fall and winter. These berries and other parts of the plant are poisonous to humans, so don't let children play with mistletoe.
Within the tough outer coat of the berry is a single seed which is embedded in a sticky pulp. Birds feed on this sticky pulp and discard the seeds which stick to their bills, feet or other parts of the body. In this way the seeds are carried to other trees or other branches of the same tree and deposited on the bark. When conditions are right, the seeds germinate, sending root-like structures into the host plant and another parasite is developed.
There are no sure fire ways to control mistletoe. You can break it off but it will eventually grow back. It is recommended that you cut a limb at least 12 inches past the mistletoe to insure that you get all the roots. This, of course, could really make your tree look bare if you take all the mistletoe out. Weed or brush killers are not recommended because they can move the chemical into the tree through the mistletoe causing major damage to the host tree or nearby plants. Mistletoe seldom kills a tree but it can weaken a tree so that it allows it to be susceptible to other diseases that can eventually kill the tree.
Whit Weems is an Erath County extension agent. His column appears weekly and online at yourstephenvilletx.com.