Get It Growing for 12/20/24

Say the word mistletoe, and many of us think of the holiday tradition of receiving a kiss underneath a cluster of green leaves.

But if you mention mistletoe to a horticulturist, you might get a different response. That’s because mistletoe isn’t exactly all fun and games. In case you didn’t know, mistletoe is a parasite — one that can steal precious resources from trees and weaken them, especially during droughts.

“Mistletoe is an evergreen, hemi-parasitic plant that photosynthesizes, creating most of its own chemical energy, or food,” explained Ed Bush, an LSU AgCenter horticulturist. “But it attaches to a host plant to receive necessary supplies of water and nutrients.”

As deciduous shrubs and trees lose their leaves with cooler weather, you might look up to discover spheres of green leaves the size of small basketballs. That’s mistletoe. It’s commonly found in water oaks but affects many other kinds of trees.

Mistletoe spreads from branch to branch and tree to tree by seeds. The plant produces small berries that contain seeds. Birds love to eat these sticky fruits. When they finish with their meal, birds often will wipe off their beaks on a tree branch — leaving behind the mistletoe seeds and giving the parasite a chance to take hold. The seeds also spread through birds’ excrement.

After a mistletoe seed germinates, a root-like structure called a haustoria forms, enabling the plant to access a tree’s water and nutrients. As a parasite, mistletoe provides nothing in return to the tree — except stress.

“The best way to control the spread of mistletoe is to prune the branch to which it is attached,” Bush said.

But removing affected branches can be difficult and even unsafe in many cases. There also are no effective chemical control options.

One thing that can help — and that is good advice anyway — is to water trees when there is not adequate rainfall. Maintaining overall good tree health helps limit the impact of stressors such as parasitic mistletoe.

Now, let’s get back to the lighter side of mistletoe. Fairies and philosophers alike have played roles in the traditions and mythology surrounding this plant.

“Nordic literature tells a story of a goddess of love named Frigg being appreciative to the god’s willingness to resurrect her son Balder, the god of light, from the dead,” Bush said. “Balder was described as so physically beautiful that he gave off light. Subsequently, the goddess Frigg made mistletoe a symbol of affection by mystically kissing all of those passing beneath the mistletoe.”

An ancient mythological tale suggests that parents place a sprig of mistletoe above a baby’s crib to ward off fairies. Another tradition involves picking a berry off the mistletoe bough each time someone kisses under the decoration.

Bush noted that mistletoe also was used to treat a variety of ailments through the centuries. In modern times, mistletoe extracts have been studied as possible treatments for prostate cancer and several other conditions.

If you want to take part in the longstanding tradition and decorate with mistletoe, Bush suggests purchasing an artificial bough. Should you decide to use the real thing, pluck off the berries, which are poisonous to humans and pets.

LSU AgCenter horticulturist Ed Bush talks about mistletoe.

Mistletoe is seen in a tree on the LSU campus. Photo by Anna Ribbeck/LSU AgCenter

LSU AgCenter horticulturist Ed Bush holds a tree branch with mistletoe growing from it. Photo by Anna Ribbeck/LSU AgCenter

Clumps of mistletoe become visible when deciduous trees drop their leaves in cooler weather. Photo by Ed Bush/LSU AgCenter