Chlorosis: The Unhealthy Yellow

Written by: By RJ Busch, Certified Arborist WI-0985A

Posted: 2020 | Plant Health Care | Summer | Tree and Shrub Care

By now you’ve had the opportunity to walk your yard (not much else to do in these crazy times) and bask in the glory of your healthy trees, but you’ve noticed that a once perfect green leafed tree is now yellow.  If you have noticed this issue, there’s good chance your tree has Chlorosis.  This disorder can affect many species of trees, but is primarily a problem with Oaks, Maples, and Birch trees.

When analyzing the yellow leaf, you may see that the veins of the leaf are green.  You may also find reduced growth, and over time, there could be major die back in the crown of the tree which can lead to the tree slowly dying.

Chlorophyll is one of the main areas of food production in a tree.  Yellowing leaves of a chlorotic tree indicate reduced levels of chlorophyll, which can lead to the tree starving to death.  One of the main factors of chlorosis in trees is the pH of your soil.  The pH is the measurement of how alkaline or acidic the soil content is. Our soils tend to have a high pH.  A high pH ties up the iron in the soil and it is not readily available to the tree

There are several ways to tackle this persistent problem.  To increase iron levels in trees, we can do a micronutrient iron soil injection, a macro-infusion of iron (FAC) in the trunk, or a foliar iron spray directly on the leaves.

Unfortunately, chlorosis in trees can be very stubborn to control.  Often you will need additional remedies to help improve your tree’s health.  Some great ways to improve the health of your tree include soil aeriation, creating a mulch bed with a layer of compost under the mulch, proper watering, and pruning any dead or declining branches.  Applying other soil injections, such as a root biostimulant, mycorrhizae, fertilizer, and compost tea, can make quite a difference in the health of your trees.  Also, having a soil or pH test done to determine your soils pH and nutrient availability.

Recommendations for your tree will be made based on the severity of the tree’s condition, site conditions, and the time of year.  Chlorosis in trees can be easily evaluated for in mid to late summer.  Call now to have a Wachtel Tree Science Certified Arborist evaluate your trees and come up with a plan to keep them healthy and beautiful.