Maybe you have to change your soil PH to 6.5.prune the oak tree.add some evergreen tree,shrub,rock.grow some fruit,vegetable.often give plant enough water,compost.
{{gwi:10161}}

It's very difficult to grow things right under trees. There may be issues of root competition. Your best bet is really to go to your local nursery to see what's available, and choose from that. I suspect what you've got there is more like dry shade. If you water a lot to change that, the tree roots may grow more into your raised bed. In my climate I might look at hostas, ferns, and hellebores to fill this, in your climate you may have more options.

KarinL