In message om,
1_Patriotic_Guy writes
Some years ago I planted 2 small blackberry shoots along the rear
fence of my yard. While I love the blackberries I get, I now have 50+
plants and they are migrating forward into my yard. Last year I dug
and removed the plants that had come too far forward from the fence.
My goal is to do something permanent to keep the grass out of the
blackberry area and the blackberries out of the grass.

My idea is to dig a narrow trench (30 to 40 feet long) parallel to and
a few feet away from the fence (basically an arms length away) and
bury something like alumninum that is sold in rolls of various widths
to prevent the roots from migrating across that border, then maybe
later putting down rock inside the border.

My questions:

1) How deep does material need to go? I am guessing 6 to 8 inches or
will the roots eventually go deeper and come under? I would like this
solution to last 20 years or more.

2) If I put some rock down where the blackberries are will I kill them
off accidentally? I want to keep the blackberries, just contain them
and have an area that still looks reasonably attractive in the winter
when the canes have been pruned back to the ground. I am guessing a
thin layer of small landscape rock might be okay or should I go with a
mulch?

3) If the alumnium is a bad idea, why, and what would you suggest
instead?

Thanks in advance for any and all help or humor.


Blackberry in the UK normally refers to plants of Rubus subgenus
Eubatus, also known as brambles. A physical barrier to the roots would
be ineffective in controlling the spread of these, as they mostly spread
by seed and by tip-layering. I haven't noticed them suckering from
roots.

However the related raspberries (subgenus Idaobatus) do sucker; I've got
some yellow-fruited raspberries, and they're suckering up to a yard away
from the parent plants. The suckers are coming from roots running about
an inch below the soil surface.

Perhaps you have one of the hybrids between these (e.g. the Loganberry)
or the American black raspberry, commonly called, fide WikiPedia,
blackberries in parts of the United States.

If you are in the United States you might be better inquiring in
rec.gardens or rec.gardens.edible.
--
Stewart Robert Hinsley