Mistletoe

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Have you ever heard of a plant with no roots? How about a plant that has no roots in the soil, but rather root-like structures that grow into other plants to steal water and nutrients?  Doesn’t that sound like something right out of a sci-fi movie?  Well, every holiday season, many of us hang a plant with these very characteristics in our homes. 

Mistletoe is a holiday favorite for many of us, but this strange plant is somewhat of a peculiarity in the plant world.  The name Mistletoe refers to a group of parasitic plants in the order Santalales.  Worldwide, they inhabit a variety of ecosystems and exist on every continent except Antarctica.  These plants are unique because they derive water and some nutrients from the host plant to which they are attached, making them dependent on the host species.

Long ago, the term mistletoe was originally attributed to the species Viscum album, which is native to the area we now know as Great Britain.  Over the centuries, the name mistletoe has been applied to a much wider group of parasitic plants, including over 1400 species around the globe.  The mistletoes we know and love here in the US, come from various species of the genus Phoradendron, many of which are native to the continental US.

Mistletoes of the genus Phoradendron are considered hemi-patristic shrubs and are evergreen, keeping their leaves year round.  They are “hemi” (meaning half) parasitic because they are capable of photosynthesis and do generate a significant amount of their own energy in the form of carbohydrates.  Some carbohydrates and water, which is essential to plant growth, are acquired from their host through a complicated plant structure called a haustorium, which is formed where root-like structures fuse to the tissue of the host plant.

Distribution of mistletoe in the US is limited by climate as many species favor our warmer, southerly states and desert regions.  They infect both conifers and deciduous hardwoods with 10 species infecting conifers and 7 infecting hardwoods in the US. 

Among the species that infect hardwood trees, the American mistletoe (Phoradendron serotinum) is by far the most prevalent in the US and can be found on over 100 species of hardwood trees across its range.  It occurs across much of the eastern US from Florida to New Jersey, across to southern Indiana and Illinois, and just slightly west of the Mississippi down to Texas.  Its range does not quite reach central Illinois due to our somewhat colder climate, although I have seen it as far north as Randolph County in southern Illinois.  

Being a former resident of southern Illinois for some 13 years, it was interesting to observe local traditions for harvest of mistletoe during the holiday season.  Since American mistletoe typically grows high in the canopy of larger, more mature trees it can be problematic collecting holiday samples. 

As a tree climber in a past career, I was asked to harvest mistletoe on several occasions, but never took the opportunity.  Since climbing large trees is typically not feasible for most folks, a ladder is often used which becomes a precarious, 2-person operation.  Some take to throwing things at sprigs of mistletoe if they are low enough in the tree canopy, although harvest success is low with this method.

By far, the most interesting and effective harvesting technique involves a shotgun which is used to shoot the mistletoe right off the limb.  Obviously, it is most effective on lower limbs, but if you are a good enough shot, it’s possible to get a few small sprigs from a pretty large maple tree.

Before you pack up the shotgun and drive to southern Illinois for a fresh bunch of mistletoe, it’s worth some reconsideration since mistletoe is actually toxic to humans and pets.  Although I typically favor fresh or live plant samples, this is one case where dried or fake samples may be our best source.  In addition, it’s not widespread in southern Illinois, being at the northern limit of its range, and you may need some inside information to find a forest canopy with this parasite. 

Please have a safe and happy holiday season and if you do happen to be in southern Illinois, enjoy the natural beauty without taking on a risky mistletoe harvesting operation.