Why Are My Vinca Leaves Turning Yellow?

Vinca (periwinkle) sometimes carries undetectable bacterial diseases like botrytis from the garden center. Once transplanted, stressed plants develop yellowing leaves—a common symptom. Weather plays a huge role: warm, dry conditions let plants power through with minimal signs, while cool, rainy weather guarantees yellowing on disease-weakened plants.

If you suspect a disease-weather combo, hope for a warm, dry spell. Water only when soil is dry an inch below the mulch. Some plants will decline and die; you may need to replace them. Fertilizer burn is another possibility, but it shows as yellowing then browning at leaf edges and tips first—not uniform yellowing across the whole leaf.