Denise is this a grass meadow with flowers or a grass path with poppies and corflowers etc in bare soil beside it? There's lots of different sorts of meadow. Grassy ones have flowers that can cope with grass competition, dog daisies, knapweed, buttercups, whatever suits your soil. If you're creating one of these on existing grass you'll need to start with plugs or even larger plants. If you're starting from scratch you can sow a wildflower mix to suit your soil after removing perennial weeds
Poppies, cornflowers, corncockle etc are cornfield flowers (or weeds if you're a farmer) and grow in cultivated soil. They can't compete wth grass. You just direct sow these as you would any annual.