Yellowing Rhododendron Among Healthy Ones: Spider Mites or Chlorosis?

Single Plant Decline = Localized Issue

1. Spider Mites (Most Likely)

• Tap affected leaf over white paper; look for moving specks (pepper-sized).
• Webbing on leaf undersides.
• Treat with **miticide** (not regular insecticide).
• Will spread to neighbors if untreated.

2. Chlorosis (Iron Deficiency)

• Young leaves yellow with green veins.
• Rhododendrons need **acid soil** (pH 4.5–6.0).
• Apply **Miracid** or acidic fertilizer.
• But neighbors would show it too if soil-wide.

Diagnosis First

Do the paper tap test. If mites: miticide. If not: soil test for pH/iron. Source: Cherie Moyer, Adams Co. Master Gardener.