Mistletoe in the tree
In the beginning of November, I was walking in a nearby Fairfax County park and noticed a dense growth of “green” above in a tree. I knew it was too large to be a bird’s nest and too green to be a squirrel’s nest. The next day I drove back to the place with a ladder and took a few photos. A branch may have fallen because when I got home it was in the car. I could quickly see that it was mistletoe with its distinctive leaves.
Think mistletoe and you think Christmas but you may also think parasitic plant that damages trees. However, the mistletoe we associate with Christmas is not a true parasite, it is a hemiparasite, which has chlorophyll and can conduct some photosynthesis but still needs the tree for nutrients and water. Thus, they do not kill their host plant.
Close up of leaves and remains of small flowers, before berries are produced
Mistletoe plants live in the tree canopy – they never touch the ground, not even their seeds. They flower and fruit, producing a white, semi-translucent berry that has a single seed. The plant depends on birds to eat the fruit and then excrete the seeds on branches. The seeds are surrounded by a sticky substance called viscin, which allows the seeds to attach to the branch. The seeds produce a hypocotyl or stem, and then it forms a structure called a haustorium, which acts like a root and burrows into the branch to gain nutrients and water.
It takes years for a plant to mature so usually one cuts part of the growth for the holiday decorations, leaving the remaining to re-grow. Interestingly, harvesting mistletoe for holiday sales is a cottage industry in rural parts of Virginia.
There are many species of mistletoe but the North America native one commonly used for Christmas is Phoradendron leucarpum, which is not toxic to humans but may cause gastrointestinal illness if eaten. The European variety, Viscum album, is toxic and deaths have been reported in Europe. This variety was introduced to the western states by Luther Burbank (American botanist, horticulturist, and pioneer in plant breeding) in the 1900s. Viscum album is native to Europe and the British Isles but is important for Americans because this is the one that inspired the holiday traditions that were carried over to the colonies in North America.
For sale at Trader Joe’s
There actually is no concrete answer as to how the holiday tradition of kissing under the mistletoe started but there are plenty of stories and folklore. It is known that by the 18th century it was a tradition in England which of course passed on to the colonies. Prior to Christmas trees, English homes hung up Kissing Boughs made up of greenery including mistletoe. It could be that a sprig of mistletoe is all that is left of those elaborate decorations that were made with a wire frame, greenery, and fruit. Because mistletoe is an evergreen plant that keeps it fruit in the winter and grows between two worlds (earth and sky), the druids believed it was magical, a symbol of fertility and vitality.
In mythology, Norse God Baldur, son of Odin, woke up one morning certain that every plant and animal on earth wanted to kill them. Frigg, his mother, and Nanna, his wife, consoled him but to no avail. Frigg asked every living plant and animal to leave Baldur in peace. They agreed. One day the gods were playing around and throwing objects at Baldur because they would bounce off him and not harm him. Jealous Loki tricked Baldur’s brother, a blind god, into shooting Baldur with a spear made of mistletoe wood. Mistletoe was the one species that Frigg failed to notice because it did not grow out of the ground but in the trees’ branches. Baldur died but Frigg learned to never forget the mistletoe. From then on, mistletoe hangs over doors as a reminder to never forget.
Regardless of the stories and myths, we now know more about the importance of mistletoe in the ecosystem. It is now considered to be a keystone species – a species on which other species in an ecosystem largely depend such that if it were removed, the ecosystem would change drastically. Mistletoe provides food: berries for birds, mammals, and fish and leaves for deer, porcupines, possums, and caterpillars of butterflies. Plus, birds and lizards feed on the insects that live in the leaves. The plant provides shelter – birds, squirrels, raptors such as hawks, and spotted owls use the mass for their nests. Fallen mistletoe leaves decay on the forest floor providing nutrients to plants, fungi, and insects. There are birds and butterflies that are entirely dependent on mistletoe for their survival. Plus, mistletoe provides early spring pollen for bees and there are some insects that feed solely on mistletoe.
So if you happen to see a green mass up in the trees, chances are it is just as important as the tree on which it lives.
Plastic mistletoe sold as a holiday decoration at Meadowlark Botanical Gardens
