North American Fruit Explorers mailing list at ibiblio

[John Jourdan <jourdanj@foxinternet.com>]

Ernie Plutko wrote concerning the growing of blackberries in northern
Minnesota.

I understand that a new extra hardy blackberry has been developed but will
not be available in nurseries for a few years.  Nurseries likely to sell
them include Fedcotrees ( Fedcoseeds.com) and Nourse Farms
(noursefarms.com). 
Blackberries that are available now would need lots of protection during the
winter to make it in zone 3.
I grow two different blackberries here in zone 4 (east of St Paul MN0. The
hardiest of the two is Illini Hardy a large upright growing plant with lots
of thorns. So far I haven't been protecting these except for a windbreak.
They are not quite hardy enough to grow here without more protection.
Usually I get only a few berries on them.
My other blackberry is Chester.  It is even less hardy than Illini but since
it is semi erect and thornless it is much easier to protect in the winter.
The berries are large and very good - ripening here about Sept 1st.
Here is how I protect my Chester blackberries:
In October we rake leaves from our yard onto a large tarp and dump them into
the blackberry bushes (after scattering mouse paks among the plants).  Long
canes are bent down or trimmed back.  I then cover with long tarps used for
covering woodpiles.  I use two 6 ft. by 25 ft.tarps for my 50 foot row.  The
6 ft tarps are hard to find but work better than the more common 4 foot by
18 ft. wood pile tarps.  About a month later I spread some straw or pine
boughs on top of these tarps (unless there is plenty of insulating snow).
Then I cover with larger tarps.  I use two 10 ft by 20 ft plus one 10 ft by
12 ft tarps.   These should go all the way to the ground -at least on the
north side. 
I uncover gradually at the end of winter after danger of severe cold is
over. 
This sounds like a lot of work but takes no more time than I spend
preparing my grapes for winter. The effort is worth it.  I have had
blackberries 3 out of the last 4 seasons.  In 2002 I picked about 100 pints.