Mystical, Magical Mistletoe
Pucker UpDecember 2014
By Laura Christman
Mistletoe is a pushy parasite—an opportunistic plant that sinks its roots into trees. The version common on North State oaks spreads by birds excreting seeds on branches. U.S. Forest Service plant pathologist Pete Angwin notes that “mistletoe,” roughly translated, means “dung on a twig.”
How’s that for seasonal merriment?
Mistletoe hardly seems the poster plant for Christmas celebrations. Yet sprigs of the self-serving plant are welcomed into homes in December. Snatching a seasonal smooch under mistletoe is a popular holiday ritual.
Mistletoe has long been a plant of mystique – sometimes feared, often revered. It’s intertwined in Scandinavian, Druid, Greek and Roman legends and rituals. The plant has been a symbol of purity, fertility, health, strength, luck and peace, according to The Mistletoe Pages, a United Kingdom website devoted to all things mistletoe. Green and lush on the bare branches of deciduous trees in winter, mistletoe was seen as a life force. Along with other evergreen plants, it became part of pagan solstice celebrations. Such evergreen reverence, while initially banned by Christian churches, eventually rolled into Christmas celebrations. The kissing custom seems to have grown out of the plant representing fertility because of its winter vigor. By the mid-1800s, London magazines were reflecting the popularity of
kissing under mistletoe, Mistletoe Pages notes.
Mistletoe legends sprang from European mistletoe, genus Viscum, which is not the same as North American mistletoe, Phoradendron. Both have evergreen leaves and white berries, but Mistletoe Pages dismisses the American cousin as lacking in symmetry and “looking, to be frank, fairly ordinary.” That hasn’t stopped Phoradendron from gaining popularity as American Christmas Mistletoe.
The North State has plenty of mistletoe. Plant pathologist Angwin, who is based in Redding and works for the Forest Health Protection branch of the Forest Service, says there are two types: Leafy mistletoe (also called true mistletoe) and dwarf mistletoe. A tree will not feel jolly about either, but dwarf mistletoe poses a much bigger risk to tree health.
The most common leafy mistletoe in the North State is Phoradendron villosum. It grows in clumps on oak trees and is easy to spot in winter. The leathery-leaved plant is able to make its own food
“Leafy mistletoes don’t cause a lot of damage to the host trees,” Angwin says. “Essentially, they extract water from the tree.” Dwarf mistletoe, genus Arceuthobium, is another story. It lacks the
thick leaves of leafy mistletoe and can’t photosynthesize, so it steals both water and nutrients from the host.
“The dwarf mistletoe has a much more serious impact because it is taking energy away from the tree,” says Don Owen, forest pest specialist with the state Department of Forestry and Fire Protection in Redding.
An infestation weakens trees, making them targets for disease and pests like bark beetles, Angwin says. Dwarf mistletoe is partial to conifers. A common species is Arceuthobium campylopodum, which latches onto ponderosa pines.
Dwarf mistletoe is only ½ to 5 inches long, Angwin says. It resembles little stems, yellow to olive in color, Owen says—definitely not anything that would pass for a holiday decoration. It has a stealthy presence in the forest.
“You can walk around and not see it,” Owen says. One way to find dwarf mistletoe is to look for witches’ brooms— proliferations of conifer branches. A hormone from the mistletoe directs new tree growth to where the parasite is attached. “They produce these plant hormones that cause trees to branch in kind of a wild fashion,” Angwin says.
While leafy mistletoe seeds spread via birds that gobble berries, dwarf mistletoe uses an explosive strategy. Each seed is encapsulated in a tiny fruit filled with sticky liquid. Pressure builds in the miniscule football-shaped capsules until they explode, shooting the seeds. Most land within 20 feet, but can go as far as 50 feet, Angwin says. “If they happen to hit a needle of a conifer tree, they’ll stick to it,” he says.
The slightest touch detonates the swollen capsules. “I used to take my kids and show them the seeds. If you touch them, they explode,” Owen says.
Dwarf and leafy mistletoes are native plants. While they don’t smack of good fortune for trees, they provide food and shelter for birds and small mammals. Birds especially like the fruits and some nest in witches’ brooms.
By the way, mistletoe leaves and berries have toxins. If you invite the parasite into your home for the holidays, keep sprigs out of reach of children and pets.