My Rosemary Plants Are Turning Brown

Soggy Soil

• Rosemary grown in overly moist soil that suffers from poor drainage generally does not do well. According to the Houston Chronicle, these plants need excellent drainage. Root rot, which is caused by insufficient drainage, will kill them by suffocation. Be particularly vigilant during heavy rains and make sure the soil is only slightly moist at all times. Only water rosemary plants occasionally, and don’t overwater when you do. If you grow rosemary in a pot, make sure the water drains out properly. Avoid watering on overcast days.

Poor Maintenance

• Improper maintenance of your rosemary plant can also lead to brown leaves. The Herb Companion recommends cutting back or pruning rosemary branches and leaves on a regular basis to encourage healthy growth. Remove dead or sagging branches. However, you should always keep at least 20 percent of the plant intact. The best times to prune are during the fall and spring, according to the Houston Chronicle.

Cold Weather

• Rosemary grows best in sunny, warm locations, according to The Herb Companion. After all, these are semi-tropical Mediterranean plants. Rosemary plants are hardy to USDA Zone 8 and will not tolerate frost. Protect your plants when the cold weather rolls in by moving them inside. Be particularly mindful of cold nighttime temperatures, as these plants do most of their growing between dusk and dawn, according to the Houston Chronicle.

Lack of Fertilizer

• Rosemary plants are not considered heavy feeders, according to the University of Tennessee Gardens. However, outdoor rosemary plants do benefit significantly from a well balanced organic fertilizer in the spring. Insufficient or poor-quality fertilizer can lead to brown leaves and eventual plant death.