Mistletoe removal from trees

Mistletoe is a flowering evergreen that grows as a parasite on a number of landscape plants in the Southwest desert. It has thick, green leaves that are oval in shape, and it grows up to two or more feet in diameter, producing small, sticky, whitish berries from October to December. Evergreen clumps of this parasite are easily seen on deciduous trees in winter when all of the leaves have fallen.

Mistletoe plants are either female or male, respectively producing either berries or pollen. Both male and female plants must exist in close proximity for pollination and fruit development. Birds feed off of the berries, digest the pulp, and excrete the seeds, which can then stick to the branches of living trees. When the seed germinates, it grows into tree tissues. It may take up to two years for the plant to bloom and produce viable seed. Seeds may also fall from mistletoe in the upper parts of the trees creating new infestations on lower branches. The parasitic plant depends on its host plant for water and nutrients, eventually causing decline over a period of years. Severe infestations cause the host tree to lose limbs and eventually die. At different elevations in Arizona and other states, mistletoe infects many trees and shrub species, including palo verde, mesquite, cottonwood, ash, sycamore, ironwood and acacia.

The most effective way to control this parasite is to prune out infected branches as soon as they appear. Cut the mistletoe from the host tree before its roots become deeply embedded in the tree limbs. Infected branches should be pruned at least one foot below the point of plant attachment. Heavy infestations may require you to remove the entire tree. At a minimum, prune the mistletoe from infected trees every six months to keep this parasite in check.