Mistletoe is an evergreen parasitic plant. There are two types of mistletoes found in California: broadleaf mistletoe (Phoradendron macrophyllum) and dwarf mistletoe (Arceuthobium spp.). Dwarf mistletoes infest pines, firs and other conifers in forests while broadleaf mistletoes grows on many landscape tree species.

These slow growing parasitic plants are spread by seed. Broadleafs are carried by birds and dwarfs seeds are propelled horizontally as they mature in distances of up to 30-40 feet away. As the seeds germinate the mistletoe grows through the bark and taps into the tree’s water-conducting tissues. Rootlike structures called haustoria form and grow within the branch absorbing both water and nutrients from the host tree. These infestations can weaken branches and can eventually kill trees, especially if trees are stressed by other problems.

To learn more about mistletoe including its lifecycle, which trees are more susceptible,  and how to best manage this parasite, please see UC IPM’s Mistletoe pest note.

I will be out of the office the rest of the week and will post a new article when I return. For food safety questions please see our previous Holiday Food Safety post. And for great tasting, nutritious left-over recipes for people on a budget see our USDA Recipe Finder post. Happy Thanksgiving!

Mature plant of mistletoe, Phorandendron sp.

Photo by Jack Kelly Clark.

Swollen limb or gall caused by mistletoe

infesting ash trunk. Photo by Jack Kelly Clark.