There are more than 1,000 species of mistletoe worldwide. All of them are broadleaf evergreens that parastically attach themselves and grow in loose twiggy balls on the branches of other trees via a root-like structure called a haustorium, which absorbs nutrients and moisture from the host plant. Unless you plan to grow mistletoe for a festive harvest, it is not encouraged. The balls tend to look unsightly rather than ornamental, and their growth habits can be harmful, sometimes killing or seriously disfiguring trees. But if you are willing to keep the ball in check, mistletoe can give you a lovely traditional decoration for the festive season.
Should you want to plant a mistletoe, the best strategy is to find berries from an existing plant and carefully mash them into the bark of a suitable tree in late fall or early winter. Most species of mistletoe have a moderate to slow growth rate and will take some time to achieve maturity.
Mistletoe can be moderately toxic to people, causing intestinal distress if berries are consumed in quantity. The berries are more seriously toxic to pets. Serious problems, including death, are possible for pets who consume large quantities of berries.
|Botanical Name||Phoradendron spp., Viscum spp., Arceuthobium spp.|
|Mature Size||3 ft. high, 3 ft. wide|
|Sun Exposure||Partial, shade|
|Bloom Time||Winter, spring|
|Hardiness Zones||5–9 (USDA)|
|Native Area||North America, Europe, Asia|
|Toxicity||Toxic to people and pets|
If you do decide you want to grow your own batch of mistletoe, you'll first need to have a healthy host tree of a species known to support mistletoe. American mistletoe prefers many hardwood species including oak, maple, aspen, ash, walnut, poplar, and elm. The tree needs to be well-established and should be at least twenty years old.
When mature berries are forced into bark cracks on the underside of well-established branches, they may germinate and develop into active mistletoe plants that will provide leaves and berries for holiday use. Be aware, though, that the mistletoe will derive its moisture and nutrients from the host tree and thus may diminish its strength. Thus, mistletoe is best suited for a large, healthy tree.
Once established, these parasitic plants will require some regular pruning to keep the heavy balls from damaging limbs on the host tree.
Mistletoe species in the Arceuthobium genus, also known as dwarf mistletoes, as considered invasive in much of eastern North America, from Canada to Mexico. The foliage of these plants is very small and scale-like, and dwarf mistletoes can parasitize many plants, including large succulents. When a dwarf mistletoe appears in your landscape, it should be eradicated, as it is not suited to use in holiday decor.
Other species of mistletoe, though sometimes damaging and disfiguring to trees, are usually not considered invasive species.
American mistletoe plants can cope with shady environments, but they do best in a sunny or semi-shade position. This is because they gain additional nutrition from the process of photosynthesis.
This semiparasitic plant gains its water from the host tree. No additional watering will be required.
Temperature and Humidity
American mistletoe is a leafy variety that needs the temperate conditions of USDA zones 5 to 9 to survive. Regions that experience harsh, sub-freezing temperatures or exceptionally dry conditions are not going to be suitable for growing this plant. In the wild, they tend to be found in low-lying ground zones that are fairly humid.
Mistletoe requires no direct feeding, as it derives its nutrients from its host plant. But it's advisable to keep the host tree or shrub well fed in order to maintain its health as it supports the parasitic mistletoe.
Types of Mistletoe
There are at least 30 types of mistletoe found in North America, some of them native, others are European or Asian species that have naturalized. These are the most common:
- American mistletoe (Phoradendron leucarpum) is the most common species growing in North America. It is used for holiday decor—though normally harvested in the wild rather than deliberately planted in residential landscapes.
- European mistletoe (Viscum alum) is the traditional holiday mistletoe. It has naturalized in some areas of North America but is more prevalent in Europe and Asia.
- Big leaf mistletoe (P. tomentosum ssp. macrophyllum) is found in the Southwest United States, from California to west Texas. It is also a popular plant for holiday decor use.
- Dwarf mistletoe (Arceuthobium spp.) is the type regarded as invasive in much of North America. There are several different species of dwarf mistletoe native to different areas of North America, each with favorite host trees.
As the haustorium establishes and grows, the mistletoe will start to develop into a ball shape and has been known to reach in excess of 100 pounds in weight and be up to 3 feet in width. Pruning back mistletoe balls will help to ensure they do not become too heavy for the branches of the trees they are inhabiting.
If an unwanted mistletoe ball appears on a tree in your landscape, you will have to cut it right back to the base and then cover the remainders with black plastic to kill it off permanently. Herbicides applied directly to new growth are also useful for eradicating an unwanted mistletoe plant.
Propagating Mistletoe Plants
Mistletoe propagation can be tricky. You need the right conditions and a suitable tree host.
- In late fall, harvest some mature ripe berries from an existing mistletoe clump on a tree.
- Squash the berries into a pulp, then press them into the bark on the lower side of strong and healthy branch on a new host tree—ideally, the same species as the tree from which you harvested the berries.
- Wait until spring, and check to see if small leaves are sprouting from the pulp. No watering or care is necessary; the mistletoe will draw all the nutrients and moisture it requires from the air and from the host tree.
Common Pests & Plant Diseases
Mistletoe is not subject to any serious pest or disease problems, as befits a plant that is often considered an undesirable weed.
How to Get Mistletoe to Bloom
The only reason to encourage a mistletoe to bloom is if you want the whitish berries for ornamental holiday use—these berries are the product of female flowers. Mistletoe does flower in later winter or early spring, but the flowers are insignificant and not worth encouraging.
If you do want to harvest sprigs with berries for holiday decor, be patient—it can take as much a four years before a mistletoe plant is mature enough to flower and bloom. Most mature mistletoe will bloom readily provided they get plenty of sunlight.
If you notice a mistletoe plant blooming, simply wait for the berries to develop. They will ripen and remain on the plant until it's time to harvest them in the early winter—it will be easier to spot the clumps once the leaves have fallen on the host tree.
Common Problems With Mistletoe
The most common complaint about mistletoe is its unwanted presence. It often arrives unbidden, usually sown by birds who spread the seeds through droppings after eating the berries. If a landscape tree develops a ball of mistletoe growth, it's usually easy enough to prune it away, though with a tall mature tree, this is best left to a professional with climbing gear. On smaller host trees or shrubs, you can do the work yourself, either by regular pruning of the mistletoe ball or by careful application of an ethephon herbicide to the mistletoe plant. Take care not to broadcast-spray herbicide, as it could potentially damage the host plant.
Simple removal of the surface growth usually leaves portions of the rootlike haustoria extending under the bark and into the vascular tissue of the tree. The mistletoe plant will often resprout, and at this point can be carefully treated with herbicide to kill the plant permanently.
Are there landscape uses for mistletoe?
These parasitic plants are not considered ornamental, and instead, create something of an eyesore on their host trees. But some people tolerate mistletoe to harvest branches for holiday displays. And these plants do make an excellent food source for various wildlife. Butterflies, bees, and other pollinators are also attracted by the nectar and pollen of the flowers, which are otherwise insignificant. Some species of birds also use mistletoe balls as roosting and nesting sites.
Does mistletoe kill trees?
Usually not, though individual branches are sometimes killed or broken by the mistletoe growth. But mistletoe does steal moisture and nutrients from the host plant and thus can lead to a tree's ultimate demise by weakening it.
Where did the "kissing under the mistletoe" tradition begin?
It is widely agreed that the tradition probably originates in a story from Norse mythology, in which the mother of Baldur, a Norse god, cast a spell to ensure that no plant growing on earth could be used to harm her son. But Loki, recognizing that mistletoe, as a parasitic plant, does not grow on earth, used the plant to make a spear to kill Baldur. By some tellings, after Baldur's death, his mother declared the mistletoe to be a symbol of love and promised to kiss anyone who passes under it. To avoid such kisses, then, was to encourage bad fortune. This interpretation is often disputed, however. The tradition of kissing beneath sprigs of mistletoe seems to have begun sometime between 1720 and 1784 in England, possibly due to a popular song of the era.
Phoradendron leucarpum. North Carolina State Extension.
Moon, Kat. Here's Why People Kiss Under the Mistletoe at Christmastime. Time.