Troubleshooting Brown Rosemary: Learn Strategies to Revive It
Rosemary, a fragrant evergreen herb native to the Mediterranean hillsides of Portugal and Spain, is a popular choice for both cooking and medicinal purposes. However, it requires specific care to maintain its vibrant green colour and aromatic properties.
If your rosemary plant is turning brown, it might be a sign of overwatering or underwatering, both of which can lead to root rot. This condition can be fatal for the plant, as it can cause the root system to shrink, potentially leading to the death of the plant.
To prevent overwatering, ensure that container-grown rosemary has adequate drainage holes and is potted in a well-draining medium. Increasing drainage is crucial, especially for container-grown plants. It's also important to avoid depleting soil nutrients by watering only when the top 2 inches (5 cm) of soil have dried.
On the other hand, underwatering can also cause brown foliage. Potted plants are more susceptible to cold temperatures than those planted in the garden, so bringing your rosemary inside or providing it protection before temperatures drop in the fall can help prevent it from turning brown.
Fungus gnats can spread rots such as Phytophthora in rosemary, another factor to consider when dealing with brown foliage. If root rot is detected, inspect the roots. If the entire root bundle is mushy and dark colored, the plant may not be salvageable. However, if some roots are healthy and white, you can attempt to cut off the infected portion and repot the "good" portion of the plant in new soil.
Rosemary is winter hardy to only about 20 F, USDA zones 7-10. Cold temperatures can cause rosemary to suddenly turn brown and drop needles. To help your plant survive cold spells, gradually acclimating it to the darker conditions of a home before bringing it indoors can help prevent root rot.
Lastly, it's worth noting that rosemary can suffer from sunburn, especially if it is container-grown, the weather is at its hottest, and the plant is already stressed. To protect your plant from sunburn, ensure it receives partial shade during the hottest part of the day.
By following these tips, you can help your rosemary thrive and continue to enjoy its aromatic properties and culinary uses.
