Trees: To Paint or Not to Paint

Two practices in orchards often create unnecessary confusion. One is painting pruning wounds with protective pastes. The other is painting tree trunks white. Though both involve paint, they serve entirely different purposes and should not be treated as similar interventions.

Let me begin with pruning cuts.

Trees do not heal the way animals or humans do. They do not regenerate damaged tissue. Instead they isolate it. A tree responds to a cut by drying the exposed wood and then sealing it off internally through a process of compartmentalisation. This is the tree’s own defence system and it works best when the cut is allowed to dry quickly.

This is precisely why pruning is best avoided during wet weather or when a spell of rain is expected. Moist conditions slow down drying and invite fungal spores to settle on fresh cuts. When we apply paint or pruning paste over a cut we trap moisture rather than allowing it to escape. In doing so we interfere with the tree’s natural process of sealing the wound. What is often marketed as protection can in fact delay healing.

For this reason I am firmly against painting or pasting pruning wounds. A pruning cut should be clean and correctly placed. It should be angled in a way that water does not sit on the surface and directed away from any healthy buds just below the cut. Beyond that the tree needs no help from us. Restraint here is the wiser intervention.

Painting young tree trunks white is a different matter altogether.

I support this practice when it is done thoughtfully and for the right reason. Many explanations are offered for trunk painting but for me there is one compelling and well observed reason. Winter sun.

In winter the sun travels much further south. Most deciduous fruit trees have shed their leaves. This allows the sun to fall almost directly on the exposed trunks of young trees. During the day these trunks can heat up significantly. This warmth is then followed by sharply colder nights. Such rapid temperature fluctuations are stressful for trees and can lead to sunscald and bark damage, especially in young ones. Dark coloured trunks are particularly vulnerable because they absorb more sunlight.

Applying a white coating reflects sunlight and moderates these temperature extremes. This simple act can prevent long term damage during the most vulnerable years of a tree’s life.

That said not all paints are suitable. The paint should ideally be a latex based formulation, preferably meant for horticultural use. Ordinary wall paints may reflect sunlight but they often contain additives that can harm living bark and restrict gas exchange. If there is no other option, I opt for the cheapest available latex paint for walls. The lower price in a way ensures that none of those expensive but harmful chemicals are mixed. Instead of latex paint some people recommend lime sulphur washes or kaolin clay based coatings. I usually avoid lime sulphur due to its effects on soil pH and on mycorrhizal networks but at times I do use these too, though I have never used kaolin clay since it is not easily available here.

I limit the application of white paint very deliberately. I paint only the main trunk of a ‘young’ tree. The coating extends from ground level up to the first heading cut which for me is usually somewhere between knee and waist height. I do not paint branches or older wood. Sometimes, I leave the northern aspect of the trunk unpainted.

Mature trees do not require this paint treatment. Their bark is thicker and naturally adapted to temperature variations. Painting old trunks is unnecessary and in many cases counterproductive. I am especially opposed to the use of chemical paints on mature trees.

There is a common belief that trunk painting is meant to deter insects or pests. That is not my intention and not my reason. In a living orchard managed with diversity and ground cover pests are addressed through ecological balance not paint.

Sometimes I also use latex paint or grafting wax to seal a fresh graft union. The intention here is not to heal a wound but to create a temporary barrier. This helps prevent the exposed tissues from drying out before the vascular connection is established and also reduces the risk of external infection during this vulnerable phase.

One interesting observation was shared by a guest who felt that painted trunks help identify young fruit trees in an orchard with dense ground cover. While that may be true in some cases it is not the reason I follow this practice. In fact many of my young trees that grow on the south side of evergreen oaks remain unpainted. They are naturally shaded from harsh winter sun and do not need additional protection.

As with most things in regenerative farming and permaculture the question is not whether a practice is good or bad. The real question is whether it is necessary. Before reaching for any paint brush in the orchard I ask myself three questions. Is the tree young and physiologically vulnerable or is it mature and well protected by its own bark? Is the problem caused by an external stress like winter sun or graft desiccation rather than by poor pruning or poor site selection? Will this intervention be temporary and allow the tree to return to self regulation? If the answer to these is yes then a light thoughtful application may be justified. If not then paint often becomes a substitute for observation patience and better design.

Observation comes first. Intervention follows only when the land and the trees truly ask for it. In a regenerative orchard like mine, the goal is not to fix trees repeatedly but to create conditions where trees need less fixing over time. Healthy soil correct spacing diverse canopies and respect for natural processes reduce the need for pastes, paints, and cures.

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