A rosemary plant can turn brown due to several common reasons mostly related to watering, sunlight, soil, pests, and environmental stress:
- Overwatering: Rosemary has shallow roots and is susceptible to root rot if the soil stays too wet. This causes brown leaves and droopy stems due to rotten roots unable to uptake water and nutrients. The soil should dry out between waterings with good drainage to prevent this.
- Underwatering: Lack of water causes dry, brittle brown leaves. Rosemary prefers periodic thorough watering followed by drying out rather than constant moisture.
- Sunlight Issues: Rosemary thrives in full sun or bright light for at least six hours daily. Too much direct midday sun can cause browning from sunburn, while too little sun leads to overhydration and browning leaves.
- Poor Soil Drainage or Heavy Clay: Rosemary prefers well-drained, sandy or gritty soil. Heavy clay or compacted soils hold too much moisture and cause root problems and browning.
- Environmental Stress: Extreme heat or cold can cause browning. Rosemary is not frost-tolerant and prolonged exposure to cold damages leaves.
- Pests and Diseases: Fungal diseases like powdery mildew or botrytis, as well as pests like aphids or spider mites, cause browning damage.
- Fertilizer Burn: Over-fertilizing can lead to brown leaf tips and stress.
To revive a brown rosemary plant, check soil moisture and adjust watering habits, ensure the plant gets adequate sunlight, improve soil drainage if needed, inspect and treat pests, avoid excess fertilizer, and protect from extreme temperatures.
