Mistletoe is easiest to spot in winter. Photo courtesy of Preservation Tree Services.
You may have noticed it as the trees start to lose their leaves, when it’s more visible. Hidden during summer, the growths look like small, lime green shrubs with waxy white berries. It’s mistletoe, a reminder of Christmas, festive decorations and the quaint tradition of kissing unsuspecting bystanders.
Don’t be fooled. Mistletoe is a vampire of the plant world. In fact, it’s a parasite that lives by attaching itself to weakened trees and sucking moisture and nutrients from their sap. Left to grow, it can shade out the tree’s foliage, depriving it of sunlight that the tree needs to internally manufacture its own food sugars. Usually, this doesn’t result in the tree’s death, just what one botanist calls “an unhappy symbiosis.”
Mistletoe grows around the world, in at least five families, according to university sources. The North American mistletoe native to Texas is Phoradendron leucarpum. Ecologist David M. Watson pointed out in a 2001 review that mistletoes have value in wild areas.
“A broad array of animals depend on mistletoe for food, consuming the leaves and young shoots, transferring pollen between plants and dispersing the sticky seeds.”
And that’s how mistletoe gets into homeowners’ shade trees. Sticky mistletoe seeds fall onto trees, dropped by birds. The seeds germinate, penetrating through the tree’s bark. When those first shoots reach the water-conducting tissue of the tree, they put out rootlike structures that grow up and down the branches, inside the bark.
“A handful of trees in North Texas are more susceptible to mistletoe,” says Micah Pace, certified arborist and professional urban forester with Preservation Tree in Dallas. ”Cedar elm, hackberry and bois d’arc. It can get on red oak and a couple of others.”
“Good tree care is the best prevention with mistletoe. Healthy trees are more resistant to pests and diseases… If you know you have a susceptible species, keep it healthy with healthy soil and consistent pruning.”
Soil aeration and mulching the root zone of the tree improve the soil and protect it from compaction. Aeration is best done, says Pace, by a compressed air tool called an “air spade,” which is a wand with a probe that inserts into the ground and injects air to open pathways for air and water.
Mulching three to four inches deep in a broad area over roots, rather than growing lawn grass there, is recommended. Foot traffic and lawn maintenance equipment running over the root zone compacts the soil, closing the natural air spaces created by earthworms, ants and the percolation of rain through the soil layers.
Once a tree has mistletoe, “address it timely and consistently,” says Pace. “If you don’t, it will continue to spread.”
Besides intercepting sunlight, the plant weakens the branches it infects, when its fibrous roots spread under the bark.
By “address,” he means, cut if off.
“It’s best to remove the branch one foot above the infestation.”
If the mistletoe has gone untreated and spread too far, deep cuts may make the tree unsightly, in which case repeated pruning is required. See Resources below for DIY guidance or professional care options.
Once this horticultural vampire is pruned away, no stake through the heart or crucifix is necessary. Dispose of it in a securely fastened trashbag or run the mower over prunings to chop them up and add them to your compost pile.
When thoroughly removed, mistletoe likely won’t need maintenance again for about two years.
And the internet lore on “How did mistletoe get its name?” and “Where did the custom of kissing under the mistletoe begin?” can entertain the easily entertained for hours.
For DIY tips on correct mistletoe pruning, contact your local Texas AgriLife Extension office. Call Steve Hudkins in Dallas County at 214-904-3050 or Laura Miller in Tarrant County at 817-884-1945. Or visit, Aggie Horticulture. For commercial help, tree care companies staffed by certified arborists or foresters are most reliable.