Posted: 06/07/2014 at 15:27
Very little grass is just grass. Most have a selection of wildflowers already there unless lawn weed killer has been used. I'd stop mowing for a few weeks and see what you've got. If you dig up and re-seed you'll allow loads of plants you haven't chosen to get a hold.
When you see what you've got you can add more. A good packet of yellow rattles spread around after the last mowing will reduce the grass and give the chosen plants more space. Dog daisies, musk mallow and lesser knapweed are among the easiest to get established in grass.
An annual wildflower mix out there would be a lot more work than grass