Rosemary bushes grow to 7 feet tall and wide in mild winter climates from South Carolina to Southern California, but if you live where winter temperatures often dip into the single digits, you will need to keep your plants indoors through the cold months.
Many gardeners grow rosemary in pots year-round, which makes it easy to move the plants inside come fall. But rosemary plants gain more size from year to year if allowed to root freely in well-drained garden soil from spring to fall. Learn to lift and transplant varieties that interest you, especially the trailing ones, which often are best in their second and third years.
For healthy, long-lived rosemary, follow these five simple steps.
1. Lift plants early. Whether you let your plants grow freely in the summer garden or keep them in pots sunk into the soil, lift them in late summer. (Labor Day is a good target date.) For the next six weeks, keep the potted plants in a sheltered spot that receives part-day shade. This will allow them to acclimate to the reduced light indoors.
2. Prune hard. As you lift plants, prune them back by about half their size. Pruned stems are great for drying.
3. Double up on drainage. Rosemary needs fairly dry soil during its winter rest. When potting rosemary for winter, line the bottom of pots with 1½ to 2 inches of fine gravel or perlite and use a fast-draining soil mix. Place pots on a saucer or tray, then water plants from the bottom by filling the saucer with water.
4. Find cool sun. Finding a 50- to 60-degree location close to a south- or west-facing window in your home could be difficult, but this is exactly what rosemary wants. Use florescent lights if none of your windows receive bright sun; for rosemary, light is much more important than temperature.
5. Use a fan. Lack of moving air encourages powdery mildew. To avoid this common problem, ventilate plants with a small electric fan. If you see rosemary leaves going white with mildew, promptly snip out the affected areas, then spray the stricken plant with a mixture of 2 tablespoons milk per cup of water. It works!
Contributing editor Barbara Pleasant, author of The Whole Herb (Square One, 2004), writes and gardens at her home in Virginia.
For the main article, The Essence of Rosemary, click here.