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Will It Hurt a Tree to Pressure Wash the Trunk?

A pressure washer is an incredibly helpful tool, but can you pressure wash a tree’s trunk? It’s essential to understand what cleaning methods may damage your trees and what alternatives there are to pressure washing.

Will it hurt a tree to pressure wash the trunk? Pressure washing a tree’s trunk can rip off its bark and cause irreparable cellular damage. Most pressure washers, even at their lowest setting, are too powerful to use on a living tree.

If you have a stained or mildewed area on your property, you can use a pressure washer to clean the section effectively. The powerful spray from the washer transforms patios, driveways, and siding from a grimy mess to a bright and attractive area that looks like new. Pressure washers are safer and more efficient when you use them on hard surfaces or inanimate objects. 

If you pressure wash a trunk covered with moss, mold, scales, or graffiti, you risk permanently damaging or killing the tree. Some trees can sustain more damage than others, but it’s crucial to learn which methods of tree cleaning are potentially damaging and which are not.

What Type of Damage Will a Tree’s Trunk Sustain If Pressure Washed?

There are several different types of pressure washers, and you have a wide range of options when choosing how much power you need. A low-end, less-powerful machine can produce 1700 PSI, but a premium washer produces 7000 PSI or more. 

PSI is a measurement of pounds per square inch, and most homeowners use washers that have a range between 2000 and 3000 PSI. You may see a neighbor use a pressure washer to clean tree trunks, but most horticulturalists and contractors warn against using washers on tree trunks.

Types of Trunk Damage

  • Bark removal
  • Cell damage
  • Chemical damage
  • Lower-Trunk and root damage

Bark Removal

Each tree has a unique bark that protects it from the weather, insects, animals, and people. The bark is like a skin that protects vital components of the tree. If you strip off more than a quarter of a tree’s bark, most trees cannot recover. 

Removing bark from a tree is easy to do if you use a pressure washer. Some trees, like pines, have brittle bark that you can remove by hand, others like live oaks have a more robust, sturdy exterior. A powerful spray is indeed more likely to dislodge the bark from a pine than an oak.

However, even the solid bark from oak cannot withstand the force from a pressure washer. Experts in tree maintenance recommend using no more than 50 to 100 PSI on a tree trunk.

An ordinary water hose produces 50 PSI, and if you add a specialized nozzle (like a fireman style nozzle), you increase the PSI to 250. High-pressure nozzles for your water hose are fine for small tasks, but nozzles producing more than 100 PSI may be too harsh for your trees.

Even if you only remove a small section of the tree’s bark, you risk leaving the tree open to attack. Wood-boring insects will take advantage of an exposed part of the trunk. 

Boring tunnels in a tree’s interior weaken the tree and make it more likely to crack or break from high winds.

Another problem you may encounter with an exposed trunk is a fungal infection. Without bark, a tree has no defense against fungi. If the fungus is left untreated, the infection can lead to abnormal growth, weakened limbs, or death.

Cell Damage

Removing a tree’s bark is terrible enough, but if your sprayer penetrates the exposed trunk further, the tree’s cambium is at risk. 

The cambium is a part of a tree’s cell network that allows tissue growth by cell division. Damage to the cambium can result in deformities, stagnant growth, or death.

It’s unlikely you would penetrate further into the tree’s trunk when removing moss or scales, but if your spray is too powerful, it’s possible. 

If you cut through the tree’s first layer of cells, you can damage the phloem. The phloem is a tree’s nutrient transport system. It distributes nutrients from the roots to the trunk and branches. If you disrupt this system, you risk losing the tree.

Chemical Damage

Although it’s less likely to occur than the previous forms of damage, chemical damage to a tree’s trunk is a possibility if you use a pressure washer. 

Pressure washers often include a separate reservoir for cleaning solutions. If you forget to turn off the valve to the cleaning chamber, you can inadvertently spray the trunk with a chemical solution designed for cleaning concrete.

Lower Trunk and Root Damage

The most sensitive area of a tree’s trunk is the lower section above the tree’s roots. This section is where the tissue from the trunk joins the tissue from the roots. 

Since the lower trunk supports the entire weight of the tree, the lower section must be strong and healthy.

If you pressure wash a tree and damage the lower trunk, you might scar the tree in its most vulnerable area. If your dead-set on pressure washing a trunk, avoid the lower region at all costs. The root system cannot pull essential nutrients from the soil if you damage it.

A scarred lower trunk can also lead to cracks. A large crack weakens the tree and makes it more fragile during heavy winds.

Can You Pressure Wash a Tree?

Under most circumstances, you should not pressure wash any section of your tree. In addition to harming the trunk, powerful spray can remove leaves, buds, and weaker branches. 

Copyright protected content owner: and was initially posted on April 14, 2020.

If you want a safer method to clean your tree, use a water hose rather than a pressure washer.

Although it’s not recommended, some people choose to clean trees with powerful washers. If you’d like to watch a stunned bystander filming a man spraying a tree with a pressure washer, click here. The man in the video stands only a few feet from the tree, and he clearly sprays the lower trunk.

If you’re adamant about using a pressure washer on your tree, here are a few tips.

  • Keep a distance of fifteen to twenty feet away from the tree
  • Use the powerful nozzle, 15° or greater
  • Never use a 0° nozzle
  • Avoid using bleach or other chemicals
  • Move the spray gun around constantly
  • Stay clear of the roots and lower trunk

In some extreme cases of vandalism, pressure washing may be necessary. If someone uses thick, oil-based paint to vandalize a tree, the tree may not survive unless the paint is removed. Some oil paints cannot be removed from a tree easily by hand, and a pressure washer may be the best tool to use.

When enormous amounts of toilet paper cover a tree after a celebration or prank, some homeowners use a low-pressure nozzle attached to their pressure washers to remove the paper. As long as you stand several feet away from the tree and move the sprayer around, you’ll minimize any damage to the tree.

Copyright article owner is for this article. This post was first published on April 14, 2020.

There was a news article regarding using a pressure washer to remove toilet paper occurred at Auburn University. After the football team wins a game, the town gathers at Toomer’s Corner to toilet paper the trees. Until 2010, a crew using pressure washers removed toilet paper from the oak trees at Toomer’s.

What Alternatives Are There For Pressure Washing a Tree?

If your trees are covered with moss or mildew, use a water hose to spray the tree. Next, use soapy water and a plastic scrub brush to remove the grime. Rinse the tree again with the hose before allowing it to dry.

If you’re trying to clean tall trees or distribute pesticides, try using a tree sprayer like this one. Unlike a pressure washer, a tree sprayer only produces 60 PSI. Orchard farmers use sprayers to apply pesticides to fruit trees safely. 

Tree sprayers produce a thirty-foot arc of water spray that becomes a fine mist at its zenith. It’s safe to use on all trees due to its low-pressure output.

Final Thoughts

Although a pressure washer is a versatile machine that makes easy work of several tasks, it’s not ideal for cleaning trees. The washer’s high pressure turns water into a scalpel that cuts away dirt or grime, but the forceful spray can also rip off your tree’s bark. 

ReadyToDIY is the owner of this article. This post was published on April 14, 2020.

If you need to clean your tree’s trunk, try the old-fashioned method. A ladder, plastic scrubber, water hose, and soapy water are all you need. If the trees are too tall for you to clean yourself, call a professional. Your trees will thank you.