What is Mistletoe?

Most shrubs stay earthbound but not mistletoe. Mistletoe likes to make its home high in the canopies of oak trees, but what is this thing? It’s a parasitic evergreen shrub that sends its root-like structures into tree branches, where they absorb water and minerals. It’s not just for kissing at Christmas time. In fact, it can cause many problems for a tree. In a severe mistletoe infestation, it can kill an oak tree (or a cedar elm). Its genus name, Phoradendron, literally means ‘thief of a tree.’

What does mistletoe look like?

Mistletoe shrubs encompass more than 250 species. It is an evergreen shrub. You can identify it easily when evergreen trees lose their leaves in autumn. From small sprigs to rounded plants, mistletoe generally arises from oak branches and twigs. In Europe, mistletoe has smooth-edged, oval, evergreen leaves borne in pairs along a woody stem and waxy, white berries in clusters of two or six. The Eastern version of this plant, found in North America is similar but has shorter, broader leaves and longer clusters of 10 or more berries.

What’s the life cycle of mistletoe?

Mistletoe is a flowering plant that produces flowers and seeds. They can be either male or female. The flowers bloom in autumn with the male flowers producing the pollen that fertilizes the female flowers. Fertilized flowers produce the telltale berries which mature over winter and ripen from late winter to early spring. Plants are usually about three to five years old before they can produce the berries, which are a favorite food of many birds. Well, the birds that are immune to the toxic berry at any rate. The excreted seeds have a gummy coating and this helps them stick to a tree. After the seeds adhere to a tree, they can germinate very easily. For seeds to grow into a shrub, they must first anchor themselves to the tree by sending root-like structures called haustoria into oak tree branches. Once the haustoria is established, the mistletoe begins to grow leaves.

What kinds of damage can mistletoe cause?

Although mistletoe contains chlorophyll and is therefore capable of photosynthesis (a mistletoe can make about 98% of its own food), it still robs the tree of water and nutrients. This parasitic plant weakens trees during periods of drought and can cause tree death. It can increase a tree’s mortality rate significantly during a drought. Mistletoe also damages trees in higher areas of bird populations and in direct proportion of tree height. The taller the tree is; the greater the chance of infection it has.

For more information on this parasitic plant, please stay tuned to our blog. Next week, we’ll talk about removing mistletoe, which is a service we are happy to perform for you. If you have questions or concerns about a possible mistletoe infestation on your trees, please contact us at 512-341-8888.