Mistletoe is a plant species from the Santalaceae family of the Santalales order. It is a hemiparasitic plant that grows attached to branches of several different species of trees. The structure by which it attaches itself is called the haustorium that enables it to obtain nutrients and water from its host plant, but it produces its food through photosynthesis from its leaves. It reaches a mature size of up to 3 feet in height and width in 10-15 years.
Viscum album (European mistletoe) is the sole species indigenous to Britain and most of Europe and was introduced in 1900 to California. Viscum cruciatum, another species, is native to Morocco, southern Africa, Portugal, and Spain.
European mistletoe has paired oval, evergreen leaves growing along the stem with white berries that form in short clusters of 2-6. The North American Eastern mistletoe (Phoradendron leucarpum) is similar, but with shorter, wider leaves and longer clusters of 10+ berries and belongs to a separate genus of the Santalaceae family.
Over time, the name mistletoe has been extended to include several other types of parasitic plants possessing similar habits in other places. They are classified in dissimilar genera and families like the Misodendraceae in Chile and Argentina and the Loranthaceae in the southern hemisphere tropics.
Viscum album parasitizes more than 200 species of trees and shrubs, with some species experiencing stunting, reduced growth, and loss of infected branches. A heavy infection might also kill the host tree.
While most of these plants have evergreen leaves stems that can effectively photosynthesize, some species that parasitize succulents grow mostly within the host, with just the flower and fruit being produced. Once these plants germinate and attach themselves to the host’s circulatory system, their production of food from photosynthesis becomes insignificant.
The seeds germinate on branches of a host and are independent during early development. Within a year or so, after the hypocotyl penetrates the bark and reaches the conductive tissue of the host, the plant starts to depend on the host to fulfill its needs that continues with the haustorium extracting water and nutrients.
The flowers of some species are insect-pollinated while others with spectacular showy flowers get pollinated by birds. Several types of birds feed on the berries, thus spreading the seeds either by their droppings or regurgitation or from having the seeds stuck to their bills which are then wiped off on branches. The seeds have a sticky coating called viscin that can attach the seeds to bark. Once the viscin hardens, the seed is firmly attached to its future host and begins germinating and penetrating the bark.
Once a plant becomes established, particularly on valuable trees, it can usually be removed by pruning the wood affected by the plant, if this is found early enough. However, some species can be rejuvenated if the haustorium isn’t removed completely.
While these plants are frequently considered harmful for trees and natural habitats, recent studies have indicated that some species are beneficial to the environment. Many animals eat the leaves, shoots, and berries of the plant for food. The plants are also used by birds for nesting places. The plant also benefits tree species by attracting berry-eating birds that eat mistletoe berries as well as berries of the host, spreading the seeds widely.
There are 1500+ mistletoe species of varying toxicity for humans, although the side effects are generally not fatal. While adults may not suffer too much from the toxins, small children and animals can suffer more pronounced side effects.
Mistletoe is important in several cultures, pagan cultures considered the berries as fertility symbols, while the Celts used mistletoe medicinally. The Romans symbolized mistletoe with love, peace, and understanding, often hanging it over entrances to protect houses. Mistletoe has also become a subject for many popular Christmas songs.
This plant can tolerate shaded environments. However, it generally thrives best under sunny or semi-shaded areas as it produces food by photosynthesis.
This plant extracts its water and most of its nutrients from its host and doesn’t need additional watering. Caring for the host tree means caring for this plant as well. Water the host tree well and keep the soil constantly damp as mistletoe plants extract plenty of water. Water the host as necessary but take care, not to over-or under-water the tree.
This plant prefers to grow in fairly humid conditions in the wild. Areas that have very dry conditions will not be suitable for cultivating this plant.
This plant is very hardy and will grow well enough in temperatures that can drop to -40°F, but this mainly depends on what the host tree can tolerate.
This plant doesn’t grow in the soil unless you’re starting the seeds in the soil.
Not applicable in this instance.
While this is a hemiparasitic plant that lives on other trees, it will only grow on specific species such as hawthorn, apple, lime, conifers, and poplars. First, identify a suitable host for the plant to grow on. This plant is a parasite, meaning it extracts nutrients and water from its host, so be careful in selecting which plant is chosen to seed. If you plan on growing the plant indoors, you will need a potted tree to attach the seeds.
Seeds are best planted fresh between March and April. Remove the seed by squeezing it out of the berry and rubbing off the sticky coating. Use a peat-based potting mix in a flat tray. Sow the seeds and mist the soil until moist. Place a transparent lid or plastic over the tray and keep the tray in an area with bright indirect light and a temperature around 60oF.
Germination could take several months depending on growing conditions. Seedlings can be transplanted after they develop several true leaves. Cut the bark of the chosen host and insert the roots, packing the cut with wet moss. Keep misting regularly until the seedling gets established on the host.
Alternatively, you can just place the seeds onto the bark of the host and mist them with water daily.
Regardless of the method used, the plant will only fruit in about 4-6 years after germination.
These plants are dioecious, either male or female, and their slow growth rate makes it difficult to tell until about the fourth year. If the plant produces flowers but no berries, then it is male. For this reason, it’s better to sow many seeds together.
This plant doesn’t need much care, but you should focus on providing the host with some extra attention and care since the mistletoe uses up some energy from it. Feed the host regularly according to the species, monitor it for pests/diseases, and keep it well watered.
Mistletoes can spread rapidly in some areas, so check whether you’re not contributing to the problem if you plant it outside. Otherwise, try growing it indoors instead.
Pruning is necessary to ensure that the plant doesn’t get too heavy for the host tree, particularly when you notice the branch is sagging or other branches of the host beginning to die. These are two indicators that the mistletoe needs pruning.
Monitor the host tree after pruning to see if it regains health. If it doesn’t recover and continues to deteriorate, cut off the entire branch and try planting a new mistletoe plant on another tree the following year.
This plant isn’t prone to damage from pests and has very few problems with diseases.