Mistletoe Weakens Healthy Trees, Knees
“A stolen kiss beneath a tree parasite.”
Tends to lose a little of the romantic flavor, huh? “A stolen kiss under the mistletoe” … much better, even though the first phrase is horticulturally correct.
Mistletoes are seed-bearing, semiparasitic or parasitic plants - meaning they grow and nurture themselves off hardwood and conebearing trees. Judging from legends, they have been “hanging around” for thousands of years.
Norse mythology tells of the death of the god of light, Baldur the Beautiful. He sort of died after being hit with a mistletoe dart. Sort of, because the gods restored him life. Anyway, mistletoe was blamed for his apparent death. That’s why, to this day, it hides in the tops of trees instead of growing on the ground.
It has also been said mistletoe has magical powers of healing and warding off of evil spirits. Romans thought that enemies who met beneath the mistletoe must kiss and declare a day’s truce.
The kissing ball came long before the Christmas tree and was actually the featured holiday decoration in many German and English homes. It was hung from the ceiling, bringing peace and happiness to the home - so long as it never touched the ground. Presents were hung from the ball while families and friends gathered underneath to sing holiday carols and to kiss.
North America is home to two types of mistletoe. The fabled holiday type is American mistletoe, phoradendron (meaning tree thief). It grows mainly on the branches and limbs of hardwood trees in the warmer regions of the U.S. Because it has leaves to soak up the sun for food production, it is considered semiparasitic. It still, however, manages to dig its little fungal roots into the branches to rob the tree of water and mineral salts.
The other type of mistletoe is a potentially harmful plant in our area. It is the dwarf, leafless type called arceuthobium or dwarf mistletoe. It is found flourishing on cone-bearing trees - in particular, on our ponderosa pine. Dwarf mistletoe can be identified by its thick, leafless, orange shoots growing on branches and twigs. Since it doesn’t have actual leaves, it is considered a true parasite, relying on the tree not only for water but for all its food.
Trees that are constantly weakened by parasites are very susceptible to disease and insect invasions. If the infestation of the parasite itself is heavy, it may eventually kill the tree.
How does mistletoe get its start? It usually takes about six years for it to complete its life cycle. Seeds that land on evergreen needles in August or September are washed to the stems and branches by rain. Here they germinate and infect the plant. About two years later, a swelling may appear on the branch. Two years after that, a number of small shoots may appear. After another couple of years, these twigs or shoots (if female) produce fruit.
Inside the fruit or berries of white, off-yellow, pink or red, are seeds nestled in a fibrous, sticky, coat. The berries are also imbedded in a sticky gelatin-like pulp that enables them to cling to the needles and bark of trees. Pressure builds inside the berry as it ripens. Come August or September, the berry explodes. The seeds are sent hurtling through the air at about 60 miles per hour and up to 30 feet. The fibrous, sticky coating on the seeds enables them to stick wherever they land. They need, however, a host plant to germinate.
The sticky berries also find an easy mode of transportation on the feet, beaks and coats of tree feeding critters. The sticky seed is also spread by birds who eat the berries. Since the seeds themselves are not digestible, they pass through the birds. Once again, the sticky fibers allow the seed to cling to just about anything.
Though control methods for mistletoe are few, there are some steps that can be taken to maintain the overall health of our trees.
Severely infected trees should be removed. Mildly infected trees should be pruned. Remove infected branches to the trunk. Ripening fruit and shoots can be sprayed with a material called Florel. This material drops the seed before it ripens. Read the label for timing and amount.
So the next time you steal a kiss under the mistletoe, remember, it’s a tree parasite you’re standing under. And you best make those kisses count. Kissing under the mistletoe has its procedures. For every kiss taken, you remove a berry. When all the berries are gone, there are no more kisses available.
The following fields overflowed: CREDIT = Phyllis Stephens The Spokesman-Review