What is Chlorosis?
Chlorosis is a serious condition where a tree’s ability to manufacture chlorophyll has been compromised. Because chlorophyll is the green pigment found in leaves, this condition is easy to diagnose by looking at leaf color. A pale green appearance to the leaves may signal mild chlorosis, while leaves may be yellow and even white in severe cases.
Why is Chlorosis a Problem?
Because chlorophyll is the molecule that a tree utilizes to make energy for itself, trees with chlorosis are making less energy than they normally would. This condition results in a weaker, less durable tree that will rarely make it to maturity. Chlorotic trees will often die without treatment.
What Causes Chlorosis?
There are a number of factors that can cause chlorosis in trees, but mineral deficiencies and root system health are among the most significant. When minerals like iron or manganese are absent from the soil or locked up by high soil pH they are not available to the tree. Similarly, if the root system is damaged or unhealthy the tree will not have the capacity to absorb these items. Without human intervention – the tree will be stuck in a decline spiral that will eventually lead to its death.
Some common reasons trees may become chlorotic include:
- Severe soil compaction
- Lawn herbicides
- Root Severing
- Deicing salt
- Root rot disease
- Repeated drought
Chlorotic trees do not produce enough energy to develop a healthy root system, and trees with unhealthy root systems do not extract the water and nutrients from the soil needed for canopy health. Without one the other languishes, and human intervention is needed to correct the situation.
Using Verdur to Stimulate Chlorophyll Production
Verdur for iron and Verdur Mn for manganese are readily available forms of micro-nutrients that last up to 3 years. A process called macro-infusion is used to evenly and completely cover the entire crown of the tree with enough active ingredient. The best time to treat trees for chlorosis is in the fall (as treatments during the growing season can result in leaf drop). Results last approximately 3 years from one treatment.
Using Cambistat to Stimulate the Root System
Cambistat has been shown in university studies to increase the size and surface area of root systems. It slows the expansion of cells in the top part of the plant which allows energy to be redirected to other parts of the plant, like the roots. It also increases a hormone that stimulates root growth, making it a good option for treating chlorosis.
Research shows Cambistat increases chlorophyll content and fine root density in trees.
Mulch Rings for Urban Trees
Certain species of trees such as river birch and silver maples have evolved in river bottoms or soils rich in organic matter. These trees have a difficult time maintaining a healthy root system in urban areas that have poor soil conditions. A mulch ring placed around these trees can provide a more favorable growing environment and help to improve the trees’ health and vitality.