How to help trees with iron chlorosis

It may feel like summer today, but fall is on the way. You can feel it in the early morning air, while you're working in your garden. Your trees can feel it too. The days are getting shorter, which means the sunlight is less intense. Tree leaves begin to adjust by producing less chlorophyll, allowing more orange and yellow pigments to show through. It's part of the process that produces our colorful fall foliage. There are many trees around town that seemed to have had "fall foliage" colors all year long. These trees, particularly maples, never turned green.

If you look closely, leaf color may vary from pale green

to a burned look, in extreme cases.

Trees that look like this are suffering from a condition known as iron chlorosis.  They need iron. They're anemic, if you will.  Left untreated, iron deficiency will eventually kill the tree. The good news is there are several things you can do to correct iron deficiency. First of all, you can apply an iron supplement to the tree. You can purchase iron supplements in liquid and granular form.

All iron supplements will help, especially those that are "chelated".

Existing trees can absorb and take up chelated irons more readily than other forms. Iron supplements should be applied now, as well as spring and summer. To fix the problem long-term, you have to fix the soil. Our native soils typically contain sufficient iron to keep trees healthy. The problem is our heavy clay, high alkaline soils prevent certain trees from taking up iron on their own. Amending the soil is the answer.

Applying organic materials such as compost, peat moss and humate will improve soil structure and reduce alkalinity. Each of these products is applied to the area under the tree's dripline, three times per year. This is easily done if your tree is planted in your lawn.

Put the HuMic down first and water it in.

Follow this with a thin (1/8" to ¼") layer of Sheep and Peat or Peat Moss and water in thoroughly. If your tree is surrounded by mulch, you can pull the mulch back past the drip line and follow the same process as above: HuMic, then Sheep and Peat or Peat Moss and water in.  If your tree is planted in rock mulch and there's no way to move the rock, consider drilling a series of holes 12" to 18", apart and 8" deep around the drip line and filling each hole with HuMic and Sheep and Peat and water in. Repeated applications will improve the soil structure, increase microbial activity and encourage the tree to take up more iron on its own. In order to assure the continued health of your trees, adding organic material and humic acid to your soil should become part of your routine maintenance. This also applies to lawns, roses, perennials and shrubs.