Iron chlorosis

unsightly

Iron chlorosis happens when a plant is deficient in iron.  This deficiency can happen to any plant, but some plants are more susceptible, like mountain ash, roses, raspberries, currents, apples, high bush cranberries, poplar and willow.

Symptoms of iron chlorosis

  • Leaves are yellow but the veins remain green.
  • There may be some browning on the margins of leaves.
  • Iron chlorosis is first seen on new growth on the tips of plants and then works back to older leaves on the branch.

What causes iron deficiency?

  • Compacted soil.
  • Soil that is saturated with water.
  • Damage to the root system.
  • Alkaline soil. Free iron is available to plant roots when the soil is between 5.0 pH and 6.5 pH.  Iron is not deficient in Prairie soils and while our soils are slightly alkaline, it is usually not enough to prevent the availability of iron. It may be tempting to try to lower soil pH, but alkalinity is not usually the problem.

How to treat iron deficiency

  • Determine if soil is compacted. See Soil compaction for information about correcting compacted soil.
  • Avoid overwatering.
  • Check automatic sprinkler system settings. Trees need about 1” of water every 7 – 10 days. Allow area to dry slightly between watering.
  • Determine if there are other reasons why the soil is continuously wet and correct if possible. (low-lying areas, downspouts or sump pump spilling on to root zone, extreme weather etc.)
  • Determine if there has been damage to the roots caused by root rot or digging in the root zone.
  • If iron deficiency is found in container plants, it may be that the soilless mix is worn out. Replace soilless mix and re-pot.
  • Apply 6% chelated iron to the leaves:
    • Follow the directions on the package. Spray on to the affected leaves and also on the root zone. It’s best to water the plant before applying it to the roots. More than one application may be needed to get a good result. However, the symptom will return if the underlying cause is not corrected.

 

Source:

Government of Canada / gouvernement du Canada. (2020, January 24). Retrieved March 24, 2021, from https://www.agr.gc.ca/eng/agriculture-and-the-environment/agricultural-pest-management/diseases-and-pests/iron-chlorosis-of-trees-and-shrubs/?id=1198883715612