We had a small wildflower garden in a raised bed last year and at the end of the season just let it die back. We haven't cleared it and not sure whether to clear it and sow more seed or wait to see if anything regenerates.
Raised Bed Wildflower Garden
Certified GKH Gardening Expert
Most wildflowers will re-seed year after year so all you need to do is water and weed!
For more information on wildflower gardens, please visit the following link: