The Homeowners Column

The Homeowners Column

Keeping Rosemary Happy This Winter

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

Until the 20th century the herb rosemary accompanied holly and mistletoe as a popular Christmas plant. What rosemary did to fall from favor is unclear. However over the last few years, she has made a comeback in wreathes and as holiday decorated topiaries. An offering of rosemary signifies love and remembrance, which is not a bad sentiment this time of year. And a sprig in your stew is quite tasty too. Rosemary is well worth growing for fragrance and flavor. She is a fairly easy going resident outdoors in the summer. The problem, however is keeping that lovely rosemary alive over the winter.

Rosmarinus officinalis is a perennial evergreen shrub hardy to zone 7. In her native Mediterranean home she can reach 6 feet tall. One rosemary plant I had for ten years grew to a huggable size. Nothing will cheer you quicker on a dull dreary Illinois day than hugging old rosemary. The pungent fragrance of pine will fill the air and all day long the aroma will remind you of your epicurean encounter.

Most homes are just too dry and too warm in the winter to suit rosemary. She likes it cool and moist. After all, her native lands are the rocky hillsides over-looking the Mediterranean Sea.

In winter when she is fairly dormant, rosemary needs a cool brightly-lit spot indoors. She is happier if the thermostat is set to 63 to 65 degrees F or lower. Also provide plenty of light with a south or west exposure. Low light produces leggy growth. A garage where the temperature doesn't drop below freezing would also work given there is plenty of light or supplemental light is provided.

If you read rosemary care instructions it will often say let dry between waterings. Good advice to a point since rosemary can suffer if soil remains waterlogged. Rosemary requires excellent drainage. Remember that rocky hillside. Letting it dry between waterings, however, does not mean it's ok to let her parch for a week. Rosemary is not forgiving if she gets too dry. As soon as the soil dries, it's time to water. I try to never let her sit dry for more than a day. I also have my rosemary in soilless mix and a well-drained clay pot so overwatering is less likely.

Around the first of May rosemary goes outdoors where she sunbathes happily on my patio until fall. I have had much better luck leaving her in the pot rather than trying to dig her up each fall. The pot could also be sunk into the ground over the summer.

Rosemary shouldn't be subjected to temperatures below 10 degrees F. Cultivars such as 'Arp', 'Athens Blue Spire' and 'Madalene Hill' are reportedly hardy to zone 6. With protection from wind and wet soil, you may get lucky and have them survive a central Illinois winter.

In the fall I let my rosemary remain outdoors until the end of October. Then she goes into an unheated porch for a couple of weeks before I finally bring her indoors. Some recommend bringing the pot indoors before the furnace is turned on.

Rosemary adds fragrance to the home as well as a pleasing flavor to cooking. Many new cultivars have been selected for their fragrant oils and ornamental appeal. If you like the way the herb smells, you will probably also enjoy the taste. Rosemary also seems to be one of the few houseplants that cats won't eat. Once you understand rosemary's needs, she can be a long-lived companion.

Interested in herbs? Attend University of Illinois Herb Day Jan 21, 2006 held at the Holiday Inn in Urbana - a full day of programs by nationally known speakers and a retail shopping area. For info PH: 217-333-7738 or e-mail preston1@uiuc.edu

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