what Ground cover between bramble berry rows?

I have made 9 12x3 hugel beds for berries, was wondering what would work as a good ground cover between the rows. There is lots of buttercup around and would like to find something that could out grow it or atleast compete, been thinking of seeding with clover. I can drive my mower between the rows if needed. Any thoughts. thks

Dan, If bramble berries are similar to black berries (and I believe they are), they have very shallow spreading roots and do not like competition in the root zone. Blueberries are the same way. Because of that, I am planting only tap rooted guild plants with my berries, including comfrey, mustard, and horseradish. None of those would be considered ground covers, of course. I have only pine straw and oak leaf mulch around my berries, and to that I add leaves from my guild plants (chop and drop) so the berries get to have all that shallow decomposing goodness for themselves the way they like it. The only tap rooted ground cover I can think of is purslane, but it's water needs are very different (it likes it dry). You're in a very different climate than I am here in Florida, so maybe there's some other tap rooted ground cover that I'm not aware of.

Any particular problem with using the buttercup as a groundcover, since it wants to grow anyway?

some buttercups are toxic..I would pull them before they go to seed. Under my brambles I have planted aegopodium and daffodills..bulbs that will spread and come back nicely are wonderful..they bloom before the brambles get busy..You could grow just about any groundcover, but my suggestion is unless your brambles are thornless not to plant anything you'll need to harvest..another nice plant with brambles is hollyhocks..they bring in pollinators...and are pretty.