North American Fruit Explorers mailing list at ibiblio

[Don Yellman <don.yellman@webformation.com>]

Mark:

The solution to your cane crowding problems may be some fundamental changes 
in your cultural practices with this cultivar, particularly with respect to 
pruning.   The fact that this very vigorous blackberry grows fast, with a lot 
of long canes, does not mean you should leave them all.  Plants should be 
spaced at a minimum distance of 4 feet apart under the trellis, and 6 feet is 
better.  The trellis should be at least 6 feet tall, and preferably a little 
taller.  Only three horizontal wires stretched across the trellis, spaced at 
roughly 18 inches apart are needed.  You can get by with two.  The top wire 
should be very close to the top bar of the trellis.  Individual primocanes 
coming up from below should be tied to the horizontal wires in a rough fan 
shape, and the main canes pinched back when they reach the top.  This will 
lead to formation of lateral canes which are also tied to the wires, and 
allowed to grow up to a length of 2-4 feet, depending on the degree of 
crowding
.  The objective is to expose all the fruiting laterals to sunlight, which 
they will need when the time comes to produce blackberries the following 
season.  Bundles of canes tied together will produce few berries of lower 
quality than fewer canes properly spaced.

As you have observed, tying all the canes together, whether at the top of the 
trellis or at any other point will result in a jumbled mess of canes and will 
not favor the production of blackberries.  If you can't spread them out on 
your trellis so that each cane is exposed to light, cut some of them out 
entirely.  Next July, when you begin picking blackberries, new primocanes 
will already be halfway up or more up the trellis.  Floricanes may be removed 
anytime after the last berry has been picked, which is not a difficult task 
if the trellis is not overcrowded.  Then you begin the pinching, pruning and 
training cycle over again with the new primocanes.

Don Yellman, Great Falls, VA