You already know a pressure washer can work magic. In just a couple minutes, you can have your worn fence or sidewalk looking brand-new. Can power washers do the same for our trees?
Tim reached out to Davey and said, “I’ve been noticing more people in my area using power washers to ‘clean’ their tree trunks.” He wanted to know if we recommended washing trees with power washers. And we often get asked if it’s okay to use a power washer to spray insecticides on trees.
So, what’s the verdict? Find out if it’s okay to use a pressure washer to spray or clean trees below.
Why You Shouldn’t Use a Pressure Washer on Trees
Pressure washers are called power washers for a reason. They are 10 to 50 times stronger than your garden hose. As you can imagine, that much power can actually hurt trees!
What happens if I pressure wash my trees to get it clean?
Pressure washers are essentially super-powered hoses. Their motor or engine intensifies the flow of water, which then sprays 1,000-to-4,000 pounds of pressure per square inch (PSI). To put that in perspective, your faucet or hose flows at about 50 PSI.
That extra force quickly wipes away grime, residue and mildew from your car, patio or outdoor furniture.
But when you use a pressure washer to clean a tree, the force removes the tree's outermost layer. Depending on the PSI and type of tree, your tree can lose chunks of its bark. And if you continue to spray, you can damage the tree cells under the bark.
Pressure washers, even when set to their lowest setting, are just too strong for trees! A garden hose and a bit of elbow grease are all you need to clean up your tree trunk. Or if you want to get rid of lichen or moss, simply pull it off. No water (or pressure) needed!
How can I do damage if I use a pressure washer to spray trees with insecticide?
This may seem like a good idea at first. But again, a pressure washer is too much for trees. If sprayed in your trees' canopy, it will likely remove or shred the leaves.
Plus, insecticides are serious business! If you spray an insecticide high up in your tree top, it’s going to rain down on you and the nearby area, which can be harmful. Professional pesticide applicators, like those at Davey, first have training and then pass a rigorous exam to become certified. That way, they know the potential risks of each pesticide–and how to use it properly.
In short, pesticides usually aren’t something you want to dabble in. Though, if you’re set on it, use a hydraulic tree sprayer with a nozzle pressure of about 400 PSI, which retails for approximately $300.