Mistletoe literally means “dung twig,” owing to its usual means of seed dispersal: a bird eats a mistletoe berry, then excretes the seed while alighting on the branch of a tree. The berry is actually a drupe, or stone fruit, and the single seed in each berry is surrounded by a viscous, persistently sticky goo, even after running through the bird’s digestive tract. Alternatively, the bird may use the branch to dislodge a seed that has stuck to its bill. Either way the seed ends up pretty much glued to the branch.
Once established the seed sprouts and sends its roots through the tree’s bark and into its circulatory system, where it absorbs water and nutrients. Mistletoe is considered a hemi- or half-parasite, because although it takes most of its sustenance from its host it also creates its own energy from chlorophyl just like any green plant. (Did you know chloroplasts, the organelles in which photosynthesis takes place, were once blue-green algae that were incorporated into plant cells long, long ago? So cool!)
Each species of mistletoe has a preferred type of tree to live on but they generally go for the deciduous types. In winter the contrast between a bare tree and its lush evergreen mistletoe topper is striking. While there are different explanations for how mistletoe became associated with kissing, humans have always cherished that which remains vigorously alive during the dead winter months.
But is it poisonous?
Well . . . kind of. But not really.
Mistletoe does contain toxins that in large enough quantities could cause vomiting as well as more serious neurological and cardiac symptoms. However, the very rare reported cases of severe poisoning have been due not to someone eating leaves or berries, which is reliably harmless, but to people drinking excessive amounts of mistletoe tea. Safe, effective medical uses for mistletoe may be discovered one day, but in the meantime keep its leaves and berries over your head and out of your cup and you’ll be fine.
Little sprigs of mistletoe, both real and plastic, are readily available in stores and farm stands during the winter holidays, but the beloved parasite is so widespread you may be tempted to pick your own. Historically, mistletoe has been harvested from its high treetop perch by blasting it down with a shotgun. If you’re fortunate enough to have access to, say, an infected apple orchard, you may be able to get by with a ladder, a little climbing ability, or perhaps a long-handled lopper.
You may be able to grow your own mistletoe although you’ll need a suitable climate, a tree for it to tap into and a great deal of patience. You’ll wait about four years to see any real action, but once established it will grow like the weed it is.
Here’s what to do:
- Obtain some mistletoe berries. Fresh is best and you won’t put them out until early spring, so if you’re starting with your Christmas sprig store the berries in a cool, dark place until at least February. You’ll want several, not only because some of them will be eaten or otherwise lost before germination, but also because they come in male and female varieties and you’ll need both if you want your mistletoe to fruit.
- Remove the seed from each berry. Keep in mind the seeds will be very sticky. It’s okay to try to wipe or scrape away some of the gooey flesh (good luck with that); they’ll adhere to the tree in any case.
- Apply the seeds to a young branch at the top of your chosen tree where they will get plenty of sunlight.
And now wait four years.