Why Do People Paint Citrus Tree Trunks White?

Excerpt from “Valley 101: A Slightly Skewed Guide to Living in Arizona,” a collection of Clay Thompson’s columns for The Arizona Republic. (Originally published October 5, 1999.)

Q: Why do people paint the trunks of their citrus trees white?

A: HA! At last, a question we actually knew the answer to without having to look it up or ask somebody. It’s to protect them from the sun.

We are soooooo smart.

To celebrate, we asked an actual newcomer in the office if she knew why citrus trunks are painted white, and she said it was to repel insects. These comical newcomers.We were going to laugh at her until we remembered she is much higher up the food chain than us and holds what passes for our career in her elegant and well-manicured hands. So we didn’t laugh.

Just to double-check, and to look busy, we called Ralph Backhaus, a professor of plant biology at Arizona State University. “It’s to prevent sunburn,” Backhaus said. “It’s really important when the trees are young.”

White Tree Trunk

White paint helps protect trees from the sun. Photo credit: Andrea Aker

Citrus trees have relatively thin bark. Left to their own, they grow more like a shrub than a tree, with shoots growing up at the base and covering the trunk.Without that shading, they need the protection of paint.

Once the canopy of the tree is thick and broad enough to shade the trunk the paint isn’t necessary, Backhaus said, but most people keep doing it anyway because they like the way it looks.

You can buy white trunk paint, but just plain old latex house paint will do. Don’t use oil-based paint — it will seep into the wood and poison the tree.

You can also, if you choose, buy trunk wraps—burlap or woven polyethylene that will protect a young tree.

Speaking of trees, you know what really frosts Backhaus’ keister? Well, he didn’t actually say this frosts his keister, but he did say it’s one of the biggest landscaping mistakes people make around here — big, cheap trees.

Bargain hunters often buy large trees that have been growing so long in containers that the roots are all jammed up and form “corkscrews,” Backhaus said. The reason they’re big and cheap is that nobody bought them when they were small and more expensive and they just kept growing in the container.

After they’re transplanted, the roots begin to grow, but because of their corkscrew shape they eventually just strangle themselves and the tree slowly dies. (This doesn’t apply to palm trees, which have different kinds of roots.)

“They’ll look good for two or three years and then they’ll just die,” Backhaus said. “People think it’s air pollution or some kind of mystery disease, but it isn’t, and these are the ones that tend to blow over in the storms.’

Comments

  1. Not trying to be smart or something, but the professor is not 100% right. It is done for a few MORE reasons then only to prevent the tree from sunburn.. Guess it also depends on in which country the trees are..

    But yes its done to prevent the tree trunk/bark from sun burn, white trunks get less warm in the sun. By painting the trunk it is also prevented from sudden temperature changes; cold night and hot day.

    Furthermore, the white paint is also an insecticide. It keeps destructive bugs from getting into the bark and causing damage to the tree. Also the insects do not like the paint and will not climb the tree, so less bugs in the tree and less bugs falling on your head! Also they will not be able to put their eggs in the tree trunk. Another thing is the white colour attracts ladybugs, who keep the tree free from some dangerous/harmful bugs. Also bugs will be more visible on the white trunk so birds can see/eat them more easy.

    Furthermore it is also done to make the trees more visible at night time, when trees line the road it reflects the cars head light so the trees are more visible, meaning the chance of hitting one reduces.

    Some people also paint the trunk white simply because they think it looks good; they use it as decoration . It creates a nice scene for photo’s and makes the surrounding place look a lot different then the normal look.

  2. Typo in the photo credit, trees not “trees”

  3. Thanks for reading Dan. We fixed it.

Trackbacks

  1. […] very special audience. Here’s a look at our most popular posts of 2011.Drum roll please…Why Do People Paint Citrus Trees White? – To celebrate, we asked an actual newcomer in the office if she knew why citrus trunks are […]

  2. […] things turn out.By Clay Thompson Read Clay’s top 10 posts to date on Arizona Oddities:Why Do People Paint Citrus Trees White? – Citrus trees have relatively thin bark. Left to their own, they grow more like a shrub than […]

  3. […] Why Do People Paint Citrus Tree Trunks White – To celebrate, we asked an actual newcomer in the office if she knew why citrus trunks are painted white, and she said it was to repel insects. These comical newcomers.We were going to laugh at her until we remembered she is much higher up the food chain than us and holds what passes for our career in her elegant and well-manicured hands. So we didn’t laugh. […]

Speak Your Mind

*