When it comes to pulling double-duty during the holidays, it's hard to beat a rosemary tree. Their appearance brings a festive touch to your holiday decor, and fresh sprigs can be used for flavoring holiday meats, breads, and desserts. Because rosemary trees are known for being a bit temperamental when grown indoors, here are some helpful tips for keeping yours healthy and happy beyond the holidays.
Temperature and Light: If you live in climate where winter temperatures fall below 30 degrees F, you will need to keep you rosemary tree inside until spring. Place it in the brightest, sunniest room in your house - a location that receives 6 to 8 hours of good light per day is ideal. Keep plants away from drafts (cold or hot). Temperatures on the cool side (50 to 60 degrees F) will keep them perfectly happy as long as they receive ample light. In the spring, when all danger of frost has passed, move the hardened off plants outdoors into a sunny location.
Watering: Maintaining the right balance of soil moisture for your plant requires staying alert. During the winter months, while the plant is in its resting phase, plants can be kept slightly on the drier side as long as you don't let the soil dry out completely. During active growing periods (spring and summer), keep them moist, but never allow them to stand in excess water. Bluish-colored leaves or a slight wilting of new leaf tips are indications that the plant is too dry.
Fertilizing: During the growing season (spring and summer), apply a half-strength houseplant fertilizer once a month (follow label directions). Do not fertilize during the fall or winter.
Pruning: Your rosemary will need to be pruned/pinched back several times during the growing season to maintain its tree-like shape. Cuttings can be kept in the refrigerator or tied into bundles and dried for culinary use.
Insects and Disease: Rosemary is generally resistant to insect attacks, but will occasionally play host to spider mites, aphids, or mealy bugs. When properly identified, most insect problems can be treated quickly and easily using organic sprays or oils.
Rosemary is susceptible to powdery mildew, a fungal disease that appears as a powdery substance on the leaves. This can be prevented by watering the plant from the bottom, keeping the humidity around the plant moderately low, and making sure the stems and leaves receive plenty of air circulation.