Chlorosis

Symptoms by part

Causes

• Soil pH that is too high, which locks up essential nutrients like iron.
• Poor soil drainage that leads to root rot and prevents nutrient uptake.
• Compacted soil that limits oxygen access to the roots.
• Nutrient deficiencies in the soil, specifically iron, magnesium, or nitrogen.

Could be confused with

• Nitrogen deficiency · Nitrogen deficiency causes the entire leaf to pale evenly, rather than leaving the veins green.
• Spider mite damage · Spider mites cause fine stippling or speckling across the leaf surface rather than the vein-focused yellowing of chlorosis.

Treatment

1. Test your soil pH to determine if it is too alkaline for your specific plant type.
2. Adjust the soil pH by adding elemental sulfur if the soil is too alkaline, following the label instructions.
3. Apply a chelated iron supplement to the soil or as a foliar spray to provide immediate relief while the soil chemistry stabilizes.
4. Improve soil drainage by adding organic matter like compost to the root zone.

Without chemicals

• Add organic compost to the soil to improve structure and nutrient availability.
• Aerate the soil around the drip line of the plant to increase oxygen flow to the roots.
• Mulch around the base of the plant to keep the root zone cool and moist.

Chemical options

• Chelated iron, apply to the soil or foliage to correct deficiency, follow the label.

Preventing it

• Choose plants that are naturally suited to your existing soil pH.
• Avoid overwatering to prevent root damage that hinders nutrient absorption.
• Use organic fertilizers that provide a steady supply of micronutrients.

When to act

Act as soon as you notice the yellowing pattern on new leaves. If the plant shows significant dieback or fails to recover after a full season of treatment, it is best to remove it and choose a species better suited to your soil conditions.

Questions people ask

Will my yellow leaves turn green again?

Usually, the affected leaves will not turn green again. Focus your efforts on ensuring that the new growth emerges a healthy, vibrant green.

Can I just add more fertilizer to fix it?

Not necessarily. If the soil pH is too high, the plant cannot absorb the nutrients even if they are present. You must address the pH first for the fertilizer to be effective.

Plants it affects

• Blueberry
• Bog rosemary
• Gardenia
• Lemon
• Papyrus
• Purple Pixie Loropetalum
• Rhododendron
• Sweetgum
• Winterberry