Painting the trunks of trees is a common practice. It is used for several purposes – to protect against sunscald, to prevent insect infestations, to discourage borers, and to reduce winter browsing by rodents. Traditionally, the tree paint most commonly used was watered down latex paint; usually 4 or 5 parts water to one part white latex paint.
Latex paint, watered down or not, is not an approved organic product. However, there is a safe formula you can mix yourself that will not only protect from sunscald and insects, it will also provide protection from soil borne diseases and help heal damage to the bark such as that from string trimmers, tricycle bumps, and backyard ball games.
Organic Tree Paint Formula One:
Compost or composted manure
Diatomaceous Earth (DE) – food grade
Soft Rock Phosphate
Mix equal amounts of compost or composted manure, DE, and soft rock phosphate. Add just enough skim milk to make a paintable slurry. Stir until well blended using a disposable paint stir stick.
Apply to the trunk with a clean paint brush. Apply thickly enough to leave a protective coat. Paint from the bottom up, applying to the bottom 18″ – 24″, including the crotches and first 6″ – 9″ of any low, lateral branches.
If this tree paint is not white enough for you, you can add whiting in equal amounts to the other dry ingredients. Whiting is calcium carbonate, or chalk, and is available at stained glass shops where it is used to clean lead glass projects after puttying.
If disease prevention or damage repair is not needed, and you are only looking for sunscald protection, here are two alternate formulas:
Organic Tree Paint Formula Two:
1- Qt. skim milk
Juice of one lemon
Whiting (see above)
Stir the lemon juice into the skim milk and set out at room temperature overnight. The next morning, strain the resulting curds through several layers of cheesecloth. Discard the liquid. Place the curds in a small pail. Add whiting to the curds a little at a time, stirring until you reach a paintable consistency. If you add too much whiting, and the mixture is too thick, thin with a bit of water.
Apply to the bottom 18″ – 24″ of the trunk as described above. This formula will be very white, and will serve as good sunscald protection. Like milk paint, this will dry hard and will last for several weeks or longer.
Organic Tree Paint Formula Three:
Place several cups of Surround WP in a pail and mix with sufficient skim milk to reach a paintable consistency. Apply to the bottom 18″ – 24″ of the trunk as described above. More than one coat may be required for adequate coverage.
Surround WP is a kaolin clay product used for insect protection in the garden. It can also be used to make a decent trunk paint that provides sunscald and insect protection. It does not kill the pests, but it flakes off onto the insect causing them discomfort. It also discourages them from laying eggs in the bark.
Discard any unused portion of these formulas. Because they include milk, they will spoil. You could store them overnight in the refrigerator if you have not completed your project, but do not store long term.
Please do not use these formulas as pruning paint. These are meant to be used as trunk paint only. We do not encourage the use of pruning paint in any case, but these formulas would not serve that purpose anyway.