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Ask the master gardener: Keep mistletoe under control in landscape

By: By Laurie Meyerpeter Placer County Master Gardener
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By Laurie Meyerpeter
Placer County Master Gardener
Question: Yikes! I have mistletoe in my tree. What do I do to remove this parasite?
Answer: Did you know that mistletoe is actually an important plant in our woodlands and wild areas providing food, shelter and nesting sites for numerous bird and insects? Recent research suggests mistletoe may be a keystone plant in some ecosystems!
Most trees can tolerate a few mistletoe plants growing in the branches but infestations may eventually weaken the tree and kill individual branches.
Biologically, it is not in the mistletoe’s best interest to kill its host as that would hasten its own demise. Mistletoe growing in one tree will not necessarily spread to different species of trees in the landscape.
Even so, it is not acceptable to allow mistletoe to grow and spread in our populated communities.
Dead mistletoe-infested limbs may fall and are a hazard. Mistletoe weakens a tree and may make it more susceptible to other pests and disease. Regular removal and management of mistletoe is recommended.
The most effective method of mistletoe management is to remove infected branches, cutting back at least one foot beyond the mistletoe to a lateral branch. Think of this as weeding the pest (mistletoe) along with its roots!
If this is not possible, cut the mistletoe flush with the branch, wrap layers of black plastic around the limb and secure with twine or tape, tight enough to exclude light but not so tight that it girdles the branch. This works like a weed mulch and prevents the mistletoe from photosynthesizing and growing.
If neither of these management methods is feasible, simply cutting the mistletoe back frequently will help prevent its spread. This is equivalent to hoeing weeds in the garden but leaving the roots; the weed is still there but it can’t produce seeds or spread.
A chemical growth regulator is also available, but since it must be sprayed on each individual mistletoe plant and is not significantly more effective than simply cutting growth off, it has few advantages.
By far the most preferred method of mistletoe management is to plant resistant trees such as “Bradford” flowering pear, Chinese pistache, crape myrtle, gingko, golden rain tree, liquidambar, sycamore and conifers such as redwood and cedar. This eliminates both the effort of managing mistletoe in the landscape and preventing the spread of mistletoe to other trees.
Winter is a good time for mistletoe management because it’s visible now.
Have gardening questions? Call the Master Gardener Hotline at (530) 889-7388.