yellowed rhody leaves - Ask Extension
I have four old (as in been there along time) rhodys planted in a row at the beach. They have landscape cloth with bark dust on them. Two that are nex...
Knowledgebase
yellowed rhody leaves #234638
Asked April 03, 2015, 7:39 PM EDT
I have four old (as in been there along time) rhodys planted in a row at the beach. They have landscape cloth with bark dust on them. Two that are next to each other look fine and the other two that are adjacent look anemic as in the leaves are much lighter green and the center rib is yellow. The leaves are decidedly sickly looking. They have looked like this for quite a few years.
Any ideas on why they look like this?
Tillamook County Oregon
Expert Response
It sounds as though your rhododendrons may have lime induced chlorosis.
Cause: A deficiency of some element, usually iron, in the plant. Iron may be lacking in the soil or in a form unavailable to plants. Lime-induced chlorosis, or leaf yellowing, is caused by strongly alkaline soil, which can make iron or manganese unavailable to plants.
Symptoms: Leaves yellow, starting at the margin and progressing inward until, in severe cases, only the areas around larger veins remain green.
Cultural control: Feeder roots are close to the surface, so work soil very lightly to avoid further injuring the plant.
- Adjust soil pH to 4.5 to 6. Adding sulfur or organic matter, especially conifer needle mulch, which is highly acidic, may help.
- Check plant's proximity to newly poured concrete. New concrete leaches lime into the surrounding soil, raising the pH.
- Use iron chelate, either as a soil treatment or by foliar feeding, to quickly help chlorotic plants. Read and follow all label instructions.
