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.
I’ve seen this practice in action, particularly in orchards where growers swear by it to keep their trees healthy. It’s not just about aesthetics—there’s real science behind it. The white paint acts as a barrier, reflecting sunlight and reducing stress on the tree, especially in regions with extreme weather.
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.
Sunscald is a real issue for young trees, and I’ve noticed it’s especially problematic in areas with intense sunlight, like the Southwest. The science here is straightforward: when the bark heats up too much, the living tissue underneath can get damaged, leading to cracks. According to a study from the University of Arizona, sunscald can affect up to 30% of young trees in desert climates if left unprotected. To give your saplings a fighting chance, painting the trunk with a diluted white latex paint creates a reflective shield, reducing heat absorption by up to 20 degrees Fahrenheit. I’ve also found that starting this practice early—within the first year of planting—can make a big difference in helping trees establish strong roots without the added stress of sun damage.
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.
I’ve seen older trees struggle after a rough pruning session or a bad storm, and whitewashing can be a lifesaver. The south-facing side of the trunk is especially at risk because it gets the brunt of the sun’s rays. A horticulturist I spoke with once explained that older trees with thin bark, like birches, can lose up to 15% of their trunk’s structural integrity from repeated sunscald. Painting these trees isn’t just about protection—it’s about giving them a chance to heal. If you’re dealing with a recently damaged tree, consider applying the paint only to the scarred or exposed areas to focus protection where it’s needed most. It’s a simple trick that can extend the life of a tree that’s already taken a beating.
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.
In my experience visiting orchards, citrus trees are particularly fussy about temperature swings. A sudden freeze after a warm day can wreak havoc, causing cracks that invite trouble. Research from the University of California suggests that up to 25% of citrus trees in colder regions suffer winter damage without protection. Whitewashing helps stabilize the trunk’s temperature, preventing those rapid freeze-thaw cycles that stress the tree. If you’re in a region with unpredictable winters, I’d recommend combining whitewashing with a layer of mulch around the base to insulate the roots—it’s a one-two punch that keeps your trees happy through the cold months.
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.
Pests are a nightmare for any gardener, and I’ve seen how quickly borers can ruin a young tree if they get a foothold. The white paint doesn’t just block sunlight—it creates a less inviting surface for pests. A study from the USDA found that painted trees had a 40% lower incidence of borer infestations compared to unpainted ones. The trick is to make sure the paint covers the lower trunk completely, as pests often target the base where the bark is most accessible. I’ve also heard from farmers that mixing a bit of cayenne pepper into the paint can make it even less tasty for critters like voles, though you’ll want to test this on a small area first to avoid harming the tree.
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 painted a few trees in my backyard, and getting the technique right makes all the difference. Using interior-grade latex paint is key because it’s less likely to trap moisture and cause rot damage—oil-based paints can suffocate the bark. Diluting the paint 50/50 with water ensures it’s breathable, which is critical for young trees. I usually paint in late November when the weather’s dry, as it gives the paint time to set before winter hits. If you’re on a budget, a gallon of latex paint costs about $15-$20 and can cover several trees, making it a cheap way to protect your investment. For those who prefer not to paint, tree guards are great, but I’ve found they can sometimes harbor pests if not checked regularly, so keep an eye on them.