How to get rid of mistletoe on trees


Controlling Mistletoe in Trees - Alabama Cooperative Extension System

Mistletoe is not usually thought of until it’s a holiday decoration. This odd plant has a long tradition of romantic, fertility, magical, and even diplomatic uses. For example, standing beneath mistletoe on a field of battle allowed Celtic warriors to rest, free of the fight.

Despite its traditional uses, mistletoe is actually poisonous to people. Eating mistletoe can cause gastrointestinal problems such as cramping and diarrhea. Compounds in the mistletoe can also slow the human heart. It’s easy for humans to avoid mistletoe poisoning—just don’t eat it. But for trees, mistletoe is a thief that will disfigure and potentially kill it. Several species of mistletoe are found in the United States and throughout the world. Mistletoe is fairly picky about the trees it inhabits. In Alabama, the most common species is the American oak mistletoe (Phoradendron serotinum), which frequently attacks oak trees but also attacks pecan, hackberry, elm, cherry, and sycamore trees.

American oak mistletoe and other rare species of mistletoe commonly infest many landscape trees. This generally happens when these trees are stressed. In fact, mistletoe infestation is often a good indicator of a stressed or unhealthy tree.

Mistletoe is common throughout Alabama and is usually noticed only when deciduous trees lose their leaves for winter. At that time of year, mistletoe stands out, being the greenest part of the tree canopy. Because mistletoe has leaves of its own, it is called an obligate hemiparasite. Obligate because it doesn’t grow in the earth and must have a host tree to live on, and hemiparastic because it doesn’t completely depend on the tree for its entire livelihood as a true parasite does.

Mistletoe is a plant and is spread by seed like any other plant. The mistletoe fruit is a white berry that is very sticky when broken. This stickiness allows the seed to cling easily to birds, squirrels, and trees. Germination is much like that of any other plant, but mistletoe roots aren’t roots. Mistletoe has rootlike structures called haustoria that grow into the tree’s sapwood. The haustoria absorb the tree’s water, nutrients, and sugars directly from the sap stream, creating a blockage in the tree’s system.

As the haustoria grow, the tree reacts with additional growth around the haustoria. Infested branches and trunks develop swollen areas around the mistletoe in an attempt to stop the mistletoe and resume unobstructed flow of sap and water.

Because we know that mistletoe grows best on stressed and weakened trees, it comes as no surprise that trees growing in cities and lawns are often infested. Our built environments (cities, suburbs, etc.) stress trees, making them susceptible to mistletoe infestation. Common stresses trees endure are soil compaction, shallow soil, rocky soil, poor drainage, poor fertility, and even root loss from digging or trenching.

The initial growth of mistletoe in a new infestation is slow and does little to the tree. Later—generally, years later—the mistletoe reaches a size that requires so much from the tree that branches beyond the infestation begin to die off because of lack of water. Often, the tree reacts to the mistletoe as if it were a disease or insect. The tree closes off the damaged portion of itself in an attempt to contain the problem, leading to more dead branches.

Whole trees rarely die of mistletoe but rather of many problems together, mistletoe being only one of them. As the amount of the tree infested with mistletoe increases, the tree becomes more and more stressed, allowing additional problems to develop. Common secondary problems associated with mistletoe are diseases and pests taking advantage of the stressed tree. Hypoxylon canker and ambrosia beetles are good examples.

Because of this scenario of mistletoe helping along other problems in the tree, the sooner you manage mistletoe, the better your chances of preventing tree disfigurement and death.

Base your decision to control mistletoe on the amount of mistletoe in the tree, how long the mistletoe has been there, and the amount of stress the tree is showing.

Improving Tree Health

The healthier your tree is, the better it can resist becoming infested with mistletoe or resist the mistletoe already in it. Good tree management always begins with creating the least stressful conditions possible for tree growth—good, uncompacted soil with proper levels of minerals, organic matter, and water.

Mulching around trees helps achieve many of these desirable conditions at minimal cost while benefiting the tree’s health. Apply mulch in a 3-inch thick layer over as large an area as possible. Completely mulching the area under the drip line of the tree is a starting point. Don’t pile mulch against the trunk as that would encourage other problems.

Pruning

Figure 1. When pruning out mistletoe, cut back to the branch collar or to a secondary branch to help the tree recover.

If mistletoe is already established in a tree, the most common control option is pruning it out. In small trees or infestations growing close to the ground, anyone can simply cut the mistletoe off the tree. However, because the haustoria are still inside the tree, mistletoe is likely to regrow. Complete control only happens when all the mistletoe, both inside and outside the tree, is removed.

To completely remove mistletoe, prune at least 6 inches below the spot the mistletoe branches are growing. When removing branches, cut back to the branch collar or to a secondary branch to help the tree recover from the removal (Figure 1). See Extension publication ANR-0258, “Pruning Ornamental Plants,” for more information.

It is also important not to over-prune your tree. The most common advice is to remove no more than 20 to 30 percent of a young, healthy tree’s canopy in a single year. If the tree is mature or unhealthy, remove no more than 10 percent of the canopy in a single year. Mistletoe removal may have to be spread over a few years to ensure that your tree recovers well.

Removing Whole Trees

Occasionally, a tree may have a severe mistletoe infestation combined with declining health that makes complete removal the best option. No clear guideline determines if you should control the mistletoe or remove the tree. The following criteria may help you decide:

How much of the tree is covered in mistletoe?

A tree with mistletoe covering 30 to 50 percent of its branches will require severe pruning, even spread over a few years. Without large parts of its canopy, the tree will not be able to make as much energy, resulting in slow wound closure that, in turn, leads to decay within the tree and an open invitation to diseases and pests.

How healthy and vigorous is the tree?

An older, overmature tree or a tree in poor health will only be able to handle minor pruning. At best, a heavy mistletoe infestation would require many years to overcome at repeated cost to the owner. Also, if the tree is in poor health, it may already be suffering from other problems that mistletoe control would make worse. For unhealthy and older trees with heavy infestations (more than 30 percent of the limbs infested), removal is the better option unless the costs of multiyear controls and treatments for tree health can be justified.

 

Download a PDF of Controlling Mistletoe in Trees, ANR-1454

How To Remove Mistletoe From Your Trees

Now that the Christmas season is over, it’s time to take down that mistletoe.

Despite its ties with the holiday season, mistletoe can have serious consequences for the health of your trees. So if you find this parasite on your property, you should remove it right away. 

So, What is Mistletoe?

Mistletoe is an evergreen plant that grows on both trees and plants. We call mistletoe a “parasite” because it draws away water and vital nutrients from its host, just like a leech takes water and nutrients away from an animal in the form of blood. 

How To Know if Your Tree Has Mistletoe

You can recognize a mistletoe infestation from the appearance of green shoots wrapped like a coil around the trunk and branches of your trees.

There are several varieties of mistletoe in the US (this US Department of Agriculture document can help you distinguish them), but they’re all fairly easy to spot. Besides growing on the branches of trees, they can be identified by their clusters of small white berries, which are poisonous to humans but a food source for many animals. Here in Texas, mistletoe grows on water oak, Spanish oak, elm, and hackberry trees, among others. If you have any of those on your property, keep an eye out.

Mistletoe Is a Tree Killer  

Over time, mistletoe’s effects can be devastating: It causes branches to weaken and eventually die. Its roots burrow through bark, deep into the inner tissue, where they sap a tree’s strength, doing lots of damage if left unchecked. If mistletoe manages to spread far enough, it can even kill entire trees, if they’re subject to another stressor. That’s why it’s important that you remove mistletoe as soon as you can. 

Mistletoe Should Be Removed Before it Harms your Tree

Mistletoe thrives on trees that are already stressed or weakened. While one or two of these parasites early in their life won’t do much harm to an otherwise healthy tree, if several of them are allowed to go unchecked, they can quickly kill branches. 

Keep in mind that if you have mistletoe on a fruit tree, it won’t be able to produce the same quantity of fruit — certainly not on the infected branch.

Pruning is the Most Common and Effective Way to Control Mistletoe

Since mistletoe is a parasite, if you cut away the branch it’s on, it will die. However, mistletoe’s roots can extend a foot or so into the host tree’s branch. That means that when pruning, you should go at least a foot past the mistletoe plant. We suggest you cut back to the branch collar. 

If you have just one or two plants on your property, and they’re in limbs that aren’t too high up, you could try taking care of them yourself. But if there are several mistletoe plants, you should have a certified arborist come out and prune them. Otherwise, the job is simply too difficult for you to complete on your own, and you’ll end up not fully removing the mistletoe, or hurting your tree more than you need to. Over-pruning is a real risk here — if you cut away more than 15 or 20 percent of a tree’s branches, you run the risk of harming it worse than the mistletoe will. That’s why removing mistletoe is sometimes a multi-year project.

Chemicals can be Used, But They’re Not a Great Idea 

If you don’t wish to prune a branch — maybe you’re concerned it will negatively affect the look of the tree — you have the option of using a chemical spray, although at Arbor Leaf Tree Care we don’t recommend it. Ethephon sprays are most commonly used for this purpose.

As mentioned, we suggest you prune rather than spray chemicals. First of all, it takes a week or two for the chemical to take action, at which point the mistletoe’s shoots dry out and fall away. Chemicals will also not get to the roots of the mistletoe. Finally, any chemicals you use will hurt the host tree. Definitely don’t use chemical spray any on a tree unless it’s dormant.

Tree Removal is a Last Resort

If mistletoe has spread throughout a tree’s branches, then pruning may not be possible. In that situation you’ll want to have an arborist come to your property and have the tree removed. Otherwise, the mistletoe is likely to spread to other trees in your yard.

You’ll Probably Have to Remove Mistletoe More than Once

Even if you prune correctly, there’s a chance the mistletoe roots have spread further than you thought, allowing it to grow back. 

Mistletoe also spreads easily — by wind, and by animals like birds and squirrels. If you’ve had it before, there’s a good chance it will grow on nearby trees in the future.

Mistletoe - a mysterious parasite on trees: how to get rid of

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  • Mistletoe is a mysterious parasite

In ancient times, this plant was considered a magical herb by the Celtic Druids. Today it is not only a promising medicinal plant, but also a popular Christmas attribute: mistletoe. The white fruits of the mistletoe ensure the spread of this plant in a special way.

Why does mistletoe grow on trees?

The English name for mistletoe - mistletoe - comes from the German word Mist, which means "litter" - not etymologically, but biologically! If waxwings and mistletoes did not love the white berries of this charming tree dweller so much, mistletoe could not spread at such a height. Since these voracious birds sharpen their beaks on branches or leave droppings there, mistletoe seeds can attach themselves to the bark of the future host tree. As the seeds begin to germinate, a young mistletoe plant emerges unnoticed. Mistletoe is a semi-parasite and sucks out the water and minerals that the tree gets from the soil. The plant, which - in a good year - stands out on the bare branches of trees in winter in the form of a lush green sphere suspended between heaven and earth, is popularly considered medicinal in Germany. In the past, this "magical plant" was called "druid grass", "thunder broom", "devil's fetters" and "witch's broom". While our ancestors hung sprigs of mistletoe on walls to ward off evil spirits, this poisonous plant is now making a career as a medicinal herb for its healing properties. Mistletoe is often used to lower blood pressure, as well as to relieve symptoms common in the elderly, and even to treat cancer.

From tradition to popular Christmas decoration

The English believe that a kiss under the mistletoe at Christmas brings good luck. This custom comes from the UK, but in Germany it has also long been popular. Ornamental evergreen sprigs are used as Christmas decorations starting in November. Just gather a few sprigs of mistletoe together and tie them with a red and white checkered bow. Wreaths of spruce branches, mistletoe and ivy with red and white berries look very stylish and beautiful. The magical effect of the berries can be especially emphasized by dividing the branches into loose bouquets and placing them in simple glass vases.

GARDENA Tip Mistletoe prefers to grow on young branches at the top of the tree canopy. As a semi-parasite, it disrupts the growth of the host tree, which is weakened by lack of water and nutrients. Therefore, in the event of the appearance of a parasite in the crown of a tree, young mistletoe plants must be removed as soon as possible, cutting them off, if possible, completely. After that, the affected area should be treated.

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is it possible to rid trees in Grodno of mistletoe — News — News and events Grodno.

Evening Grodno

The branches were cut, the mistletoe remained

The general opinion of the townspeople was expressed by the reader of Vecherka Lilia Boysha: “The streets and yards are full of mistletoe, especially on birch trees. In the yards, the trees are cut in such a way that you are amazed: no shade, no greenery. It's as if no one sees the mistletoe. Now, while there are no leaves and the pest is clearly visible, it's time to deal with it.

Our readers have reported many places where trees are affected by mistletoe: near secondary school No. 8 on Vasilka street, in the yard of house No. 22 on Karbysheva street, on Lenin street, 24, near Rumlevsky bridge, Mound of Glory, on Boldin street, BLK, Gorky, Pushkin…

Grodno residents not only talk about the problem, but also ask themselves the question: when will public utilities begin to free crowns from pests? “Somewhere,” the townspeople report, the public utilities nevertheless got there, but the effect is not the one that was expected.
“Eight branches were cut from the trees opposite residential building No. 18 on the BLK, and the mistletoe, along with the crows, remained. We hope that we will be heard! We do not accept a tick about the work done, ”says one of the SMS messages to the editor.

Is the parasite so terrible?

Senior lecturer of the Department of Botany and Plant Physiology of the Grodno Agrarian University Svetlana Rodionova explained that mistletoe is a scourge of deciduous trees, it causes the tree to dry out and ultimately die.

- Mistletoe sucks organic matter, minerals and water out of wood. She is the cause of the dry tops of trees, because substances do not reach the branches that are above her. The tree stops growing, but the mistletoe grows. Later, under the weight of her bushes, the branches begin to break, - says the specialist.

The parasite spreads easily and quickly, infecting neighboring trees:

- Mistletoe spreads with the help of fruits. The bird eats a white berry and flies to a healthy tree. Digestion in birds is fast, and the seed, which is not digested, comes out in less than half an hour. It sticks to the bark and begins to sprout.

Is there a way to fight?

Mistletoe begins to bear fruit, and therefore infect neighboring trees, not in the first year of life. Escape with leaves appears a year later. The huge bushes that we most often see on trees are evidence that the mistletoe has been growing unhindered for about ten years. The saddest thing is that there is no effective way to combat the parasite, and the whole of Europe suffers from this.

- Sprouting, mistletoe immediately puts haustoria under the bark, which sucks useful substances. They envelop the tree inside, and every year the network grows larger. Chemicals cannot be used - they will greatly damage the "owner," explains Svetlana Rodionova. - The only way to prevent the spread of the pest and prolong the life of the tree is to cut the shoots. The tree, of course, still remains infected, and a new shoot will appear later. But he needs fewer substances for nutrition than a huge bush, while there will be no fruits for a long time.

Why is there more mistletoe every year?

Grodno residents note that 10–15 years ago there was almost no mistletoe in Grodno, but now the problem seems to have taken on an urban scale. Svetlana Rodionova names several reasons that contributed to the spread of the parasite, including in forests: a general warming of the climate and cutting down trees. It has become warmer, there is no natural shade created by densely planted trees - all this contributes to the successful photosynthesis of mistletoe.

As Alexander Rusak, chief engineer of Grodnozelenstroy, explained, municipal services are not engaged in purposeful pruning of mistletoe in the city. It is removed during planned molding or sanitary pruning.

- Mistletoe has to be cut together with branches, because there are several bushes on them at once.


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