Hi Laura,

Himalayan blackberry has very deep roots (over 15 feet deep in ideal conditions), so after it is mown, the regrowth mostly comes from these crowns and roots. These roots store a large amount of energy and can access water deep in the soil profile, allowing the plant to grow back and outcompete other species of plants grown from seed. This is one of the reasons this species is so invasive in our region. 

What this means for management is smothering with a cover crop alone most likely will not be effective since you are competing with established plants, not seedlings. My suggestion is to develop management plan with the understanding that you are guiding the space to gradually change. This would consist of regular mowing or grazing to exhaust the roots of the blackberry overtime, allowing other plants to eventually take over. This could be a mowing every late spring or rotating goats through the area periodically. If plowing is an option, this could really help speed up the removal of blackberry, followed by a competitive grass.

As for a smothering cover crop, suggestions would change depending on what you want for the space. Is this going to be a grazing area, do you want to plant an orchard, a garden or have it as an open space/ wildlife area? If you let me know what your hopes for the space, we are can identify a seed mix that would help.

Hi Laura, 

That sounds great, my recommendation is a native grass heavy seed mix. The general recommendation is to use grass because the thick matting root systems make it harder for both seedlings and regrowth from the crowns to come up. 

Native grass seed mixes can be very pricey and there are few carriers, so a grass blend heavy on fine fescues with some perennial ryegrass is recommended. 

Thank you and I hope this is helpful.