Sunburn, Insect Damage and Pruning Desert Museum Palo Verde

Q. I had my yard re-landscaped in June and with it I planted a Desert Museum Palo Verde. After planting, I pruned it and maybe removed too much which caused some sun damage. My great aunt used a lime and water "paint" on her trees to repel critters and I’m wondering if this might help.

A. The time of year it was planted probably had something to do with the damage you’re seeing. The lime and water paint was used in the past mostly to reduce sunburn from intense sunlight. The reduced damage from painting the trunk and limbs attracted fewer insect problems.

Fruit trees with trunks painted in Afghanistan. This was probably done by someone from an NGO and not done by locals for insect  and sunburn control in Balkh Province.

lime and water concoction

            But painting trees with this concoction was also used to make them look prettier. It’s still done for ornamental purposes in some countries. Now we paint the trunk and larger limbs of fruit trees with dilute white latex paint mostly to reduce damage from boring insects attracted by injury from intense sunlight. That’s its primary purpose.

Plant at the Right Time of Year

            First off, planting trees and shrubs in the spring or fall months leads to more success and less damage than planting during the summer months. Palo Verde, like most landscape plants, should be planted in late January or February or late September and October for best success. Those spring and fall months are more forgiving than planting during the heat of the summer.

Transplant Shock

            Secondly transplant shock, or the “interruption in growth” of plants when moved from a container into the landscape, is more dramatic during the heat of the summer than during the cool spring and fall months. Transplant shock that time of year varies from almost nonexistent to severe branch dieback depending on the care given when planted.

Dig the hole and planting depth

            Dig the planting hole three times the diameter of the container and make sure plants go into a wet planting hole as quickly and carefully as possible. Never plant into a dry hole even if you add water immediately after planting. Damage from planting that time of year during the summer in coastal California might be minor but not in the Mojave Desert.

            Make sure plants are planted at container depth and, after planting, have not sunk deeply into soft, wet soil. This can be difficult to detect after planting and is a major cause for plants that struggle and eventually die after planting.

Water Deep and Not Often

            Water this tree under the canopy with enough water to wet roots 24 inches deep. Irrigate again to keep the soil moist at this depth, but not wet. Irrigating frequently and deep enough to keep soils moist will cause your tree to stay full, grow quickly and recover from sun damage. When it gets larger, reduce how often the tree is watered but not the volume of water applied.