Getting
Rosemary through the Winter

Rosemary is a tender perennial in USDA hardiness Zones 5 and 6, which
includes most of Massachusetts. This means it can live for years, but it must
come in for the winter or it will freeze to death.

Rosemary has particular requirements for optimum growth and health. It needs
full sun and likes warm, well-drained, slightly alkaline soil that is neither
too wet nor too dry. It can do fine in the ground or in a pot, as long as its
requirements are met.

Here are some suggestions to get rosemary through the winter and back into
your garden the next spring.

Potting: Texas
potting. This is a method of potting your rosemary that allows you to
better regulate the moisture content of its soil. See our handout on Texas
potting.*

Indoors: Rosemary must
come inside in the fall; it will freeze and die if left outside. It can
take temperatures down to 25 degrees F, therefore
it will survive a light frost. But get your plant inside before major
frosts set in.

Light: Rosemary needs
light! If rosemary does not get enough light it gets very leggy and
unhappy. Either place your rosemary in a very sunny window or use a plant
light (one with a bulb specifically for plant growth). South or west
facing windows are best. If using a plant light, give your plant about 16
hours/day of light. A timer can help to keep the light consistent.

Mildew control:
Rosemary is subject to powdery mildew, a white, powdery dusting that
appears on the needles and sometimes the stems. Untreated, this will cause
your plant to drop needles and eventually to die. There are a couple of
ways to deal with powdery mildew:

Adequate air circulation- make sure there is air space around
your plant. Using a fan to lightly circulate air nearby can help.

Baking soda spray- when you see the first signs of
powdery mildew, spray your rosemary with this mixture:

1 quart water

¾ teaspoon baking soda

1 drop dish detergent

1 drop vegetable oil

Place
in a spray bottle and use when needed. Will last
indefinitely.

Timing: Don’t
put your rosemary plant back outside until we’ve had our last major
frost, usually by the middle to end of May. And remember to get it in
early enough in the fall.

Happy growing!

* Texas Potting instructions are posted on
our website: www.neuhsa.org

"Getting Rosemary through the
Winter" was written by Iris
Weaver, a member of The New England Unit, Inc. of The Herb Society of
America, Inc. All rights reserved.