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13-03-2005, 10:29 PM

wrote:

We just moved to Mid-Michigan from Northern California. Just about the
only thing we miss about our old house was the ability to grow herbs
year-round, particularly rosemary. We would like to find a way to keep
rosemary bushes alive through the winters here (zone 5b). I've read
that it is sometimes possible with the hardiest varieties in sheltered
areas.

We just replaced the original furnace in our 50 year old house and as
part of the installation, a new exhaust pipe was routed to our
foundation in the backyard. The result is a lot of warm, steamy air
comes out of the house near the ground in a particularly sunny spot.
I'm wondering how I could take advantage of this situation for the
rosemary. One idea I had was to make some sort of cold frame near the
vent to capture the heat without shocking the plants too much. Any
suggestions?

What you want to do is grow something in a climate that is
definitely not suitable. You will find that all evergreen
perennial herbs are either very difficult or outright impossible to
keep alive through the winter unless you have a greenhouse with
controlled climate. The conditions inside a house in winter, while
suitable for people, is not suitable for rosemary -- too warm and
too dry.

You might also find that the summer rain in Michigan (a rarity in
much of California, where rain is much more likely in winter) keeps
the soil too wet for rosemary, which thrives in a Mediterranean
climate -- cool wet winters, hot dry summers.

Also, don't try to grow citrus in Michigan either. Instead, try
growing plants that appreciate a cold winter and that don't thrive
in the mild winters of coastal or southern California. That
includes many spring bulbs, apples, pears, and lilacs. While I
can't get tulips to repeat from one year to the next because of a
lack of winter chill, they should readily naturalize in your new
home.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at URL:http://www.rossde.com/garden/