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?

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?

give it a try, but don't be shocked if it fails. suppose you have 30
people in the house while the temperature outside is near 0F. The
furnace won't kick in very often and the rosemary will freeze to death.
same if you heat with a wood stove. the coldframe alone will give you
1.5 extra zones but you probably need three. a double layer coldframe
may just do the trick but if strong winds knock it down, even once?
That is all it takes.

My Michigan rosemary is in a 12 inches pot that comes in in october and
goes out in april. Rosemary will take frost, which is why it goes out
so early, and is undemanding as a potted plant (needs watering half the
time compared to a regular houseplant for example, and little
fertilization). That plant grows strongly (it is a very thick 2 feet
bush) and gives us plenty rosemary. We also have large outdoor
perennial patches of mint, sage, lemon balm, thyme, and oregano, all of
which grow easily here, and I dry pounds of leaves in july and
september. thyme, sage and oregano last well into december, so don't
get discouraged.

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/

David Ross wrote:

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/

It would be nice to have pictures to go with your words.

--

Travis in Shoreline (just North of Seattle) Washington
USDA Zone 8b
Sunset Zone 5