Xtremehorticulture

Black Plastic Under Rock Problems

Q. I’ve read somewhere that you should not
place black plastic under rock used for desert landscaping. I have it there. We
are an older couple and cannot remove it easily. Can we do anything else?

Black plastic under rock mulch tears and deteriorates in a few years. Shouldn’t be used under rock.


A. I realize you understand that using black
plastic is not a good idea under the rock. Using plastic under rock mulch in
desert landscapes prevents air from reaching the roots. Roots need water, but
they also need to “breathe”. Black plastic is not permanent while rock is.
Sooner or later, this black plastic will begin poking through the rock mulch as
it is punctured and disintegrates.
            Consider
punching air holes through the plastic at the base of trees and other plants to
help air reach the roots. The downside of this recommendation is it may cause
the black plastic to rip and disintegrates sooner, peaking its ugly head
through the rock.
            Don’t
think you have to remove all this plastic at once. If you see some sticking up
through the rocks, remove it until more appears.
            A
more expensive option instead of plastic is called a “weed barrier”. This is
spun or woven material that “breathes”, allowing air and water movement. I
personally don’t particularly like weed barriers because they do not prevent
many of our most troubling weeds like common Bermudagrass and nutgrass. Instead
I would recommend spending a little bit more money on rock mulch and applying
it thicker, perhaps 3 – 4 inches deep instead of two.

Leave a Comment

Your email address will not be published. Required fields are marked *