Mistletoe is important for many insects too. Their early-blooming flowers are important nectar sources for bees and other pollinators when not much else is available, and many insects only live on mistletoe foliage. Three butterfly species in the US are mistletoe obligates (meaning their caterpillars can only feed on mistletoes), but only one, the great purple hairstreak (Atlides halesus) is found in the Chesapeake Bay Watershed.
American mistletoes rarely kill their host tree; their life history strategy is to remain with the host and produce berries as long as possible, so they need their host to survive. Recall that dwarf mistletoes, on the other hand, die after ejecting their berries. They do not need their host to remain healthy and can weaken their host substantially, increasing the likelihood of mortality. Dead trees are critically important for cavity-nesting birds and roosting bats, and once they fall over, a host of organisms that will live in or consume the log. Dead trees also mean more light to the forest floor, allowing vigorous herbaceous and shrub growth and enabling seedlings and saplings to grow into the next generation of canopy trees. These small canopy gaps are functionally patches of young forest, where the flush of vegetative growth yields more food and cover for wildlife. Many species require canopy gaps to successfully breed, and they are also important cover and food sources to deer, wild turkeys, ruffed grouse, bats, and other forest wildlife.
Like many of our traditions, appreciation for (and yes, kissing under) mistletoe developed and evolved as societies rose and fell. European mistletoe (of the genus Viscum) closely resembles leafy American mistletoe, so European colonists and subsequent immigrants easily transferred their customs over to North America. Many European cultures, from the ancient Greeks to the Nordic peoples and the Celts, revered oak trees. Viscum mistletoes grow on oaks and stay green throughout the winter, when the trees have lost their leaves (and, it was possibly thought, their “life forces”). This is likely why mistletoes were imbued with such importance, especially over the winter; they held onto life when even the mighty oak could not. They were seen as vessels of strength and vitality and were often used in ceremonies marking the winter solstice, which of course are mirrored today by Christmas and other traditions and celebrations around that time of year.
As Christianity swept through Europe the old traditions became muddled, but mistletoe remained an important winter symbol. It was often hung in doorways to deter demons and witches, and was widely thought of as a universal healer. The custom of kissing beneath it may have come from the belief that it stimulated fertility, or perhaps from an ancient Norse myth that resonated through the centuries. In the story, the beloved son of Frigg, the goddess of love and beauty, was killed by an arrow made from mistletoe. The gods all agreed that the plant should never hurt anyone again, but rather be dedicated to happiness and usefulness. Frigg’s tears became the white berries of mistletoe, and the goddess swore that she would kiss anyone who walked beneath it.
No matter what the origin of the kissing custom is, American mistletoe makes a lovely winter decoration. Rather than an excuse to smooch, it’s a great opportunity to talk to guests about forest ecology and the fascinating biology and cultural history of this strange little parasite. Look up into the empty branches of oaks and sweetgums for a cheery clump of mistletoe this winter. It will likely be too high up to reach, but that’s a good thing; mistletoe is a valuable member of our forests and will do a lot of good up there in the treetops.
Above information is excerpted from: