By: Jean Ferdinandsen, Certified Arborist WI-0149A
Leaves and needles of most trees and shrubs are supposed to be green. When they stop being green in mid to late summer, they may be suffering from chlorosis.
Chlorosis is a yellowing of foliage due to the loss or breakdown of chlorophyll. The result is a paling of the normal green color to yellow or even white. The foliage may appear uniformly pale or variegated. Growth is often reduced, storage reserves are depleted, and trees are more susceptible to other issues when in this condition. Chlorotic trees are unable to manufacture enough of their own food supply. If left uncorrected, chlorosis will weaken the tree and eventually lead to death.
Trees such as oaks, white pines, birches, silver and red maples are especially susceptible to chlorosis. This can be caused by poor soil conditions, construction, compaction, root loss, lack of nutrients, or high pH. All of these conditions inhibit the tree’s ability to absorb the nutrients and micro-nutrients it needs, which leads to chlorosis.
Chlorosis often appears slowly, over many seasons. The reversal of chlorosis and regaining tree health is also a gradual process. There is often no single cause, nor a single cure for this condition. Building up and maintaining a full, healthy root system is critically important.
Treatments may be varied and multi-pronged, depending on the site conditions and severity of the chlorosis. Because each situation is unique, treatments and/or combinations of treatments will not always be the same for every tree.
Potential goals in treating chlorotic trees include:
- lowering soil pH to improve nutrient availability
- improving root growth
- alleviating compaction
- improving soil texture
- improving root systems for better uptake and storage
- reducing stress
- providing supplemental nutrients to increase availability and uptake
To achieve these goals, your Certified Arborist at Wachtel Tree Science and Service may recommend a combination of measures or treatments. These include:
- proper watering
- soil aeration
- mycorrhizae inoculation
- root stimulants
- micronutrient fertilization (usually iron [Fe] or manganese [Mn])
- macro-infusion of nutrients into the trunk (FAC or Mn)
Recommendations for your tree will be made based on the severity of the tree’s condition, site conditions, time of year, and the most cost-effective manner of treatment. Trees are most easily evaluated for chlorosis in mid to late summer, when leaves are present. Call now to have a Wachtel Tree Science and Service Certified Arborist evaluate your tree and make recommendations as needed.
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