Chlorosis is the yellowing of leaf tissue
due to the lack of chlorophyll. The green, light absorbing pigment,
chlorophyll is need for the production of food and lack of this can
severely stunt, weaken or kill a plant. Micronutrients such as iron,
manganese and zinc are essential for chlorophyll production. Conditions
such as poor drainage, compact soil or root damage can limit the plants
ability to absorb these nutrients. Besides the three listed conditions,
alkaline or high ph soils is one of the main reasons for chlorosis.
At a ph of 6.5 or higher, iron becomes more insoluble, effecting the
plants ability to absorb it. In southeastern Wisconsin the soils are
limestone based resulting in alkaline soils. Plants such as Red Maples,
Pin Oaks, River Birch, Azalea, Rhododendron, etc., all suffer from
chlorosis.
Chlorosis of a Red Maple.
A leaf showing the typical symptoms of green veins
and yellow leaf tissue.