blackberries

Asked April 21, 2020, 7:01 PM EDT

How do I clear an area full of blackberry bushes and salad for planting, I only have a tiller and hand tools? I would like to put rhodies and hydrangeas there. But I can't put down gardeners fabric because it is a hillside and a large area. Ground cover? I also have a pretty newly planted orchard that is being taken over by blackberry bushes. I pull try to pull them out. How can I keep them from coming back? The area was forested at one point, then covered with Salal before it was cleared by backhoe. Ph is around 6.5. The fruit trees are doing pretty well. I haven't been able to get any ground cover to grow to discourage the blackberries. What would you suggest? It is just so much work to pull the berry bushes out and they seem to grow back 10 fold the next year.

Lincoln County Oregon

1 Response

Blackberry is tough - it spreads by seed, root sprouts, and by cane tips that readily root when they touch the ground. The best way to deal with blackberry is with physical control methods like you've been doing. It may be a very time-consuming, repetitive process. With proper timing, you may be able to blend your physical control methods with some targeted chemical control methods. You probably would not want to try any broadcast chemical control on blackberry in your orchard because of possible negative effects on your trees. Ground cover would probably only help prevent blackberry seed establishment - it would have no effect on root sprouts and lesser effect on spreading by cane tips. Annual rye grass could be seeded to provide some relatively quick cover.

Salal spreads also underground with rhizomes and must be physically removed or blocked from the surface with a barrier like heavy landscape fabric.

After you clear a small area of blackberry or Salal (including digging up root balls and rhizomes just below the surface of the soil), go ahead and plant your hydrangea and rhododendrons. As the grow, the shade they produce will help to deter blackberry seedlings from developing. Keep an eye out for any blackberry or Salal popping up in the area where you've planted - remove them before they get going. This will allow you to make some slow steady progress without totally wearing yourself out.

This OSU Extension publication provides some useful information regarding blackberry control including selective use of chemical control. https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1594.pdf

Also this Nature Conservancy document has some very useful information for you to consider. https://www.invasive.org/gist/moredocs/rubarm01.pdf