How to Remove Mistletoe

Mistletoe, the cheerful holiday decor, is a parasitic landscape pest.

Typically associated with the holiday season, mistletoe is a troublesome parasitic pest that threatens a handful of landscape trees, including birch, ash, walnut, flowering pear and cottonwood. The evergreen plant produces clumps of green stems with thick, oval leaves and tiny white berries that absorb nutrients and moisture from the host tree, causing branches to become weak or even die. Although most trees tolerate mild mistletoe infestations on a few branches, heavy infestations reduce vigor and cause stunted growth or death, unless treated.

Things You'll Need

• Pruning shears
• Black, thick polyethylene
• Tape
• Ethephon spray
• Disease-resistant trees
• Chain saw
• Shovel

Instructions

1. Prune out branches in your yard around which mistletoe grows. The root or haustoria of mistletoe grows inside the stem or branch of the tree on which it is growing, therefore complete control is achieved if you cut the entire limb off. Using sharp, sterilized pruning shears, cut back infected branches down to 10 to 12 inches below the point of the weed attachment to ensure complete removal.

2. Cut off the mistletoe flush with the trunk if you cannot remove the major branch around which it grows. Wrap black polyethylene or another opaque material such as duct tape or tar paper over the area to help keep sunlight out. Avoid wrapping the material too tight when securing it with tape, as you could damage the branch. Mistletoe thrives in sunlight, so preventing access to sunlight kills it in two years. Inspect the opaque material regularly and fix immediately if it comes loose, to prevent mistletoe regrowth.

3. Spray branches of dormant host trees with ethephon to control mistletoe growth. Follow label directions when applying the spray over the foliage in spring, when temperatures begin to warm, but before new growth appears on the tree. Direct the flow of spray only on the mistletoe growth, not the tree. Repeat treatment on mistletoe that grows back.

4. Remove severely infected trees from your landscape and replace with resistant varieties. Cut the trees down to the ground with a chain saw, and dig out the remaining stump out of the soil. Although drastic, this is perhaps the best control measure. Mistletoe-resistant varieties include subalpine fir, rocky Mt. juniper, white fir and Engelmann spruce.

Tips & Warnings

• Ethephon is a growth regulator that promotes responses such as flower induction and fruit ripening. It prevents mistletoe from producing seeds and infecting other trees, thereby controlling spread. Although it does not completely control mistletoe growth, it helps reduce it.

• Use ethephon spray on trees that are dormant, not when they are actively growing and covered with leaves.

References

• University of California Integrated Pest Management Program; Mistletoe; February 2006
• Mississippi State University; Mistletoe in Landscape Trees; Dt. Frank Killebrew; January 1997
• University of California at Davis; Mistletoe; E.J. Perry, et al.
• Parasitic Plants; Controlling Mistletoe; September 2005