Garden

Getting rid of invasive blackberries

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Q: I paid a gardener to pull out and dig as much of the blackberries in my yard as he could last fall, then I covered the area with black week proof cloth. I then fastened it down with anchors and place 2×4’s over that. The blackberries are pushing through and coming up in other areas. I do want to use this as a vegetable garden, but can’t seem to stop this problem.

Invasive blackberries can be a pain! Its removal techniques tend to be site-specific, and might work better at one site than another. So choose the most effective method for preparing your ground for future projects.

Blackberry-Specific Removal Techniques:

  • Mowing and cutting – Oregon State University extension-weed scientist Jed Colquhoun suggests cutting the vine to ground level, especially during springtime when the plant is most actively growing. Cutting the vegetation back might be tedious and time-consuming, but it will eventually kill the plant. This method is ideal for turning the patch into a lawn.
  • Digging – pulling the plant out by its roots is another effective method. Though it requires some hard labour, it’s specific in destroying only the invading blackberries while preserving the nearby vegetation. When digging, make sure to remove the crown of the root. The key to this method: persistence.
  • Goat grazing – For the daring individuals out there, here’s a method to think about. Australians and New Zealanders have been using this technique to great effect since the 1920s. But do you really want to introduce an animal that might create a bigger problem than your invading plant species? It’s your call!

For more on goats in the garden, go to Carol Pope’s blog entry here.

Plant problem and pest expert, Conway Lum, has this to add:
“With patience and persistence, keep removing the top blackberry growth and the plant should become weaker, especially if it is growing in an isolated area. Covering the area with a black landscape fabric can assist in controlling the blackberries, but the method is not foolproof as the vines have extensive root systems that will try to emerge. Assuming there is no other desirable plant in the ground, e.g. roses, herbs, perennials, etc., try putting a heavier layer of bark mulch, about 30 cm (12 inches) thick or more, to increase the smothering effect. By adding a thicker mulch, you make the blackberry work harder to come to the surface, making the plant even weaker.”

For more information regarding blackberry removal, please see: https://www.pesticide.org/pubs/alts/blackberry/blackberries.html

For information about getting rid of invasives generally, check out Carolyn Herriot’s blog entry here.