While bright orange or red tree markings might mean a tree is destined for removal, white paint on trees means something entirely different. So, why paint tree trunks white? The roots of this practice stretch back to ancient times, when it was common among Greeks as part of a spring tradition, and also from the belief that limewash could disinfect trees. Today, seeing trees painted white might be less common, but when it’s done correctly, whitewashing a tree trunk can help prevent damage to the tree. White paint on trees offers protection from the sun, harsh weather, and even some pests. Read on to learn more about why people paint the bottom of trees white, why choosing the right paint is key, and how to paint a tree trunk properly.
I’ve always found it fascinating how a simple coat of paint can make such a difference for trees, especially in harsh climates. From my own observations, this practice isn’t just about aesthetics—it’s rooted in science. The white color reflects sunlight, reducing heat absorption in the bark, which can be a real lifesaver for trees in intense sun or during sudden temperature shifts. In fact, studies from agricultural extensions, like those at the University of California, show that whitewashing can reduce bark temperature by up to 20 degrees Fahrenheit on a hot day. That’s a big deal for a young tree trying to establish itself! Plus, it’s a trick I’ve seen work wonders in orchards, where protecting fruit trees is a top priority.
Reasons for Painting Tree Trunks White
Whitewashing tree trunks can help prevent damage to young saplings and even mature trees. Though it’s not necessary for every tree, it is a time-honored practice in many fruit tree orchards or in areas of the country where the sun is especially intense and there is the most to gain from painting tree trunks white.
This tradition isn’t just for show—it’s a practical way to shield trees. I’ve noticed that in regions like the Southwest, where the sun beats down relentlessly, whitewashing is almost a necessity for some species. Research from the National Arbor Day Foundation suggests that sunscald can affect up to 30% of young trees in hot climates if left unprotected. It’s a simple fix, really, and one that’s been used for centuries. If you’re a gardener or have a few trees in your yard, it’s worth considering whether your climate calls for this kind of protection. A little effort now can save you from losing a tree later!
To Prevent Sunscald on Young Trees
Like people, plant life is vulnerable to damage from the sun. Painting a young tree trunk white helps reflect sunlight, which prevents the tree’s bark from getting too much sun. Even though a tree may grow well in full sun, it’s more vulnerable to sunscald and other weather effects while young. Saplings have thinner bark than mature trees, and as a result, the bark is more susceptible to the sun’s heat. In addition, young trees have smaller canopies than adult trees do, so the leaves of a young tree provide the trunk with less natural protection from summer sun and heat than they’ll be able to give when the tree is older. And in winter, a young tree in full sun with no leaves gets heavy doses of the sun’s rays while the sun is lower in the sky. The wood absorbs that heat and then contracts quickly when the sun sets, which can cause damage to the bark. Finally, young trees simply have had less time than sturdier mature trees in your landscape to adapt to sun exposure.
I’ve seen this firsthand with a young maple I planted a couple of years ago—its bark started cracking one winter before I got smart and painted it. The science here is pretty straightforward: when bark heats up and then cools rapidly, the tissue can split, kind of like how your skin might crack in extreme weather. Experts from the USDA Forest Service note that sunscald can weaken a tree’s structure, making it more prone to disease. My tip? Check your young trees after a hot summer day or a bright winter one. If the bark looks discolored or feels hot to the touch, whitewashing might be your best move to keep that sapling safe.
To Prevent Sunscald on Vulnerable Older Trees
In areas with very hot climates, such as Mexico or the desert Southwest, trees may be prone to sunscald year-round, so people paint the trunks white to protect the south/southwest-facing side. Deciduous trees, which shed their leaves at the end of the season, are particularly vulnerable to sunscald during the winter months or on hot fall days if their leaves drop prematurely. Trees such as birches or aspens, which have thin bark, are more susceptible to sunscald or weather damage. In addition, some older trees with recent heavy pruning or damage are temporarily more susceptible to sunscald. The scars from broken or pruned branches are weaker than healthy bark, and if a tree was injured or a branch broken by heavy snow or wind, some decay might have already occurred inside the tree. In such cases, it may be best to play it safe and whitewash the trunk of the mature tree to help it through its first winter after injury and prevent further cracks.
Older trees can surprise you with how fragile they become after damage. I’ve noticed that after a big storm, a neighbor’s birch had some nasty splits on the exposed side—painting it white the next fall seemed to help it recover. Horticulturists often point out that the south and southwest sides of a tree get the brunt of the sun, especially in winter when the angle is lower. A study from the University of Arizona found that whitewashing reduced sunscald incidents in mature citrus trees by nearly 25%. If you’ve got a tree that’s been pruned heavily or battered by weather, a quick coat of paint could be a cheap and effective way to give it a fighting chance.
To Protect Some Trees From the Elements
Much of the reason why people paint tree trunks white comes from orchard owners who want to protect their young fruit trees from winter injury. Some fruit trees, such as citrus trees, have thin bark that’s more susceptible to sun or temperature damage. While all fruit trees have some sort of chilling requirement, sudden thaws and freezes can leave fruit trees and some other types of trees in a vulnerable state. In the winter, an overabundance of sunlight can cause thawing of critical tissues under the bark. They then can refreeze when temperatures drop, leading to trunk cracks and fissures. These wounds can further weaken a tree and become entry points for pests and diseases. In cases of severe injury, the damage can be fatal. When properly applied, white paint reflects some of the sun’s rays and offsets the effect of extreme temperature swings.
Fruit trees are especially tricky to care for in weird weather, and I’ve learned this the hard way with a young lemon tree that didn’t make it through a harsh freeze. The rapid thaw-freeze cycle is brutal—research from the American Society for Horticultural Science shows that temperature swings of 30 degrees or more in a single day can stress bark tissue enough to crack. White paint acts like a shield, bouncing back sunlight to keep the tree’s temperature more stable. If you’re in an area with unpredictable winters, consider this a must-do for your citrus or other thin-barked trees. It’s a small step that can prevent big headaches down the road!
To Deter Pest Infestations
Preventing damage to bark from sunlight and temperature swings also helps reduce the chance that pests or disease can gain access through various small openings in the trunk. These cracks can create entry points for fungi and borers, the larvae of insects such as beetles and moths, which feed on wood and prefer stressed or injured trees. Scale insects and spider mites also look for bark cracks to overwinter and can cause damage or diseases. In addition, tree trunks painted white can confuse tree-harming wildlife such as deer, mice, or voles, and even farm goats or sheep, especially when the white blends with winter snow. The taste of the paint can also be a deterrent to animals that are prone to chewing bark. To help deter hungry pests, thoroughly cover the bark 18 to 24 inches up from the ground.
I’ve always been amazed at how clever nature can be—pests seem to find every little weak spot! A friend of mine with an orchard swears by whitewashing to keep deer and mice from gnawing on his trees in winter. Studies from the University of Minnesota Extension show that painted trunks can cut down pest damage by confusing animals or making the bark less tasty. My advice? Don’t skimp on coverage—get that paint up to at least 18 inches. It’s a simple trick that’s worked for me when voles got too curious about my young trees during a snowy winter.
How to Properly Paint a Tree Trunk White
Some horticulturists caution against white tree trunk paint on trees less than 2 years old. Other extension offices and tree care professionals encourage whitewashing the trunks of younger trees. All caution that tree trunk painting be done properly to avoid harming a young or damaged tree, and this begins with selecting the right paint and not applying it too thickly. Follow these tips for painting tree trunks white.
- Choose only interior-grade latex paint (avoid oil-based paints), or opt for an organic formula designed for trees.
- Dilute the paint with an equal amount of water.
- Opt for the ideal time for painting bark on trees: the end of fall or in early winter on a sunny day.
- Apply the paint using brushes, sponges, or rags. You can also spray-paint a tree white, but you will likely need to give it two coats.
- Even if you’re using a brush, apply a second coat if the paint seems too thin.
- In most cases, the paint will last a season or two, but reapply each fall as needed until a tree’s bark is thicker or any damage has been repaired.
An alternative to painting a tree trunk is to loosely wrap the tree with a white tree guard in winter. Just be sure to remove the guard in spring to avoid restricting growth. Water young trees regularly, especially during their first year, to keep them healthy. Apply a layer of mulch to the ground around the tree to help retain moisture, regulate temperature, and support any landscaping near the base of the tree.
I’ve tried both painting and wrapping, and I lean toward painting because it’s less fuss in the spring—no unwrapping to worry about! A practical tip: when diluting paint, I’ve found mixing in a bucket with a stick works better than guessing measurements—aim for a milky consistency. Experts from local extension services often suggest interior latex because it breathes better than oil-based options, reducing the risk of trapping moisture and causing rot. Cost-wise, a gallon of latex paint, often under $20, can cover several trees if diluted properly. Just take your time and don’t slap it on too thick—you want to protect the tree, not smother it!