FLORIDA — Recently, I have been asked about mistletoe growing in trees and whether it is harmful. Perhaps, people notice mistletoe more often during winter. This may be because clumps of green mistletoe stand out in leafless dormant trees this time of year.
In Florida, mistletoe is most common in oaks, particularly in laurel oaks. It can be found in other tree species, including sycamore, wild cherry, and elm.
Mistletoe is a parasite and can harm trees. It also has poisonous properties and should be kept out of the reach of children and pets who may be tempted to eat the berries.
Being a parasite, mistletoe gets water, essential elements, and some food from its host tree. As more clumps of mistletoe grow, the tree may decline. Old, slow-growing trees are most susceptible. Mistletoe seldom infests young, vigorous trees.
Every clump of mistletoe is male or female, not both. Only female clumps produce the white to pink-colored fruit. Each berry contains a sticky seed inside.
Mistletoe is spread mainly by birds. Birds eat the fruit, and then seeds pass through the birds and stick to branches. Falling fruit from clumps of mistletoe can stick to limbs below. Once a seed is stuck or lodged on the branch, growth of a new plant can begin.
Seeds germinate and grow a root-like stub that works its way into bark openings, eventually becoming connected to food supplies within the branch. It may take several seasons for leaves to develop while the root stub continues to grow within the branch.
Mistletoe is difficult and, in many cases, impractical to control due partly to the way it’s connected to the tree. And mistletoe growing high up in the tree is difficult to reach.
Just breaking away the mistletoe is ineffective because it may redevelop at the point of removal. Systemic herbicides applied to the mistletoe can move through the mistletoe into the tree, injuring the tree.
Ethephon, a growth regulator, has been used to control mistletoe but must be applied by a licensed pest control operator, can damage a tree when used incorrectly, and provides only temporary control.
The most successful method of eliminating this parasite from a tree is through proper branch removal. The entire limb should be pruned at least one foot below the point where the mistletoe is attached.
Once mistletoe has been removed, there is always the chance that additional mistletoe will again find its way to your tree via birds.
More information is available at the following UF/IFAS website.: https://sfyl.ifas.ufl.edu/lawn-and-garden/mistletoe