I thought it was exterior latex??

Carla in Sac

Any latex is the latest.

Trunk painting is done to protect new, tender young bark on many fruit trees from sunburn as well as boring insects. Avocados are a good example of fruit trees whose bark is very thin, and can be sunburned and seriously damaged if the receive too much sun while still young. Here in S. California, it is the hot summer sun that is our culprit. In colder areas of the country, it is known as Southeast trunk injury, and can be a problem for young fruit trees. This type of damage can occur on sunny winter days even though temperatures may be quite low. Sunlight
striking the tree trunk can raise the temperature of the bark on the lower trunk to as high as 80 or 90 F. The cambial tissue under the bark will lose hardiness. When the sun goes down, trunk temperatures will drop to the same temperature as the air. If this temperature drops below a critical point, these sensitive tissues will be injured or killed. This can be fatal to a young fruit tree. Out here in California, we use white or a light-colored interior latex paint cut in 1/2 with water. You may need two coats if you have a particularly vunerable tree. Never use an oil-based paint, as it can burn the bark. I would check your local state Cooperative Extension office or Master Gardeners for more info in your area, as well as fruit tree growers.

Patty S.
(Advanced Master Gardener, Elkhart County, Indiana 2005)

Here is a link that might be useful: Planting and Care of Young Fruit Trees - UC Davis Cooperative Extension

Has anyone ever tried any color other than white? Any experiments out there?
I know one would think white would reflect more light, but if the protection is in the layer of paint, what difference would the color make? Obviously black would create too much heat, but I was thinking of trying a "tree bark" color like tan or grey.

Carla in Sac

Commercial growers use the paint to provide some protection from Roundup injury as well, although research has not yet confirmed its efficacy according to an article I just read.

And that's southWEST injury. It's the sun that hits it in the afternoon before sudden drop in temps after sunset.

Is their any research that shows paint offers protection from borers?

Fedco recommended mixing joint compound with latex paint, which would be the opposite of thinning with water. It is supposed to help against borers. I applied that thickly to all my young fruit trees in fall of 2009, then wondered over the winter if I might have killed them all, since no one else had ever mentioned doing this. They were all fine in spring of 2010, and so far have had no borers. As the trees grew over the summer, the coating just cracked apart to allow for expansion. Come fall, I gooped up the new trees I planted in 2010 and smeared more on the ones I had done the previous fall. Painted it as high as I could reach--a messy job. I put hardware wire enclosures around the trees against rodents and 6' tall woven wire cages against deer, also. This year the snow is deep, so I hope no skinny rabbits have gotten through the woven wire to nibble low branches. The neighbor's cat helps keep down the rabbit population. I have many varieties of sweet and sour cherries, plums, apples, pears, and apricots. Only the apples have born fruit so far. Northwoodswis

OP: http://cecalaveras.ucdavis.edu/files/58343.pdf

The below article also discusses using Lime and/or Salt mixed in the paint.

.

Regarding color: I've painted my young peaches with peach-pink colored paint and my orange trees with bright orange paint. Seemed to work ok /shrug.

Here are three of the little genetic dwarf peaches/nectarines painted peach color:

{{gwi:58900}}

Here is a link that might be useful: UCDavis Whitewash Tree Trunks

I work at Apple Works Orchard in Trafalgar, Indiana and one big reason we use white paint on our apple tree trunks is because in the winter when it gets cold the bark on the trunk gets cold at night and when the sun heats it up in the afternoon it expand from the heat. This expanding can cause the bark to crack and expose the tree to disease and pests. The white paint reflects the light that the dark bark would normally absorb. Therefor, the bark does not get so hot and hopefully won't split. White reflects the most light (heat from the sun).

Here is a link that might be useful: Apple Works

Why on earth would you go to the trouble of making a white wash when latex paint can accomplish the same thing?

I never paint trunks in my nursery except apricot trees (in a probably futile attempt to stop them from breaking out of dormancy prematurely) and I never suffer from southwest injury here in southeastern NY except on older trees that have been excessively pruned.

>>when latex paint can accomplish the same thing? It can do allot more,...it doesn't wash off!

sautesmom
I use brown "oops" paint from Home Depot. Five dollars a gallon and it matches the trees. I also boil old cigarette butts down and add the juice to the paint as it acts as a pesticide, similar to black leaf, and further deters pests. I find the un-cut paint fills in cracks and crevasses better, sealing off areas insects lay eggs.

Brown may be too dark for CA., and caution with the nicotine juice..... not to get it on your skin as it is poison.

Has anyone ever not diluted the paint and used this as protection against borers and rabbits. Will it girdle the trunk? I was thinking of trying it on a few trees. For rabbit and borer protection.

I didn't dilute the paint on my two citrus trees. I didn't do ENOUGH research beforehand. It's also light blue. I guess we'll see. ...I have one young lemon that isn't doing so well even before I painted it and a lime that is showing new growth.

see my review:

http://forums.gardenweb.com/discussions/1516623/comparison-of-3-painting-mixtures-for-trunk-protection

I was at the zoo this weekend and noticed a lot of their trees were painted blue. It looks really nice. They paint them blue as some sort of tree awareness program. I thought about painting my crape myrtle in my front yard blue just because it looks awesome. However it looks very tedious.