I have a large bed next to the house that was previously covered in
overgrown shrubs. We removed the shrubs when we bought the house last fall,
and I made the naive mistake of assuming that since the bed was completely
free of any grass or weeds by late April, it would stay that way. I planted
sunflowers in the back (which have come up nicely) a densely sown
wildflower mix, then some shorter flowers (e.g., poppies) around the border.

All of those seeds have been slow to sprout, and while some have, I now see
a dense covering of what looks like grass coming up around the edges.

I did not properly prepare the bed!

I seem to have two options:

1) Let things go a little wild and enjoy whatever flowers (perhaps the ones
farther from the edge) that come up this summer. At the very least, there
will be sunflowers

2) Start over and replant half the bed with transplants

I am happy to do #1 (my focus on the first year of the house was building
vegetable beds and planting fruit trees--in other words, edibles, not
flowers). However, my question would be, how well would seeds sown in
mid/late april compete with whatever seeds were already in the ground? Am I
likely to get a tangle of weeds and grass if I let it go wild?

If I do #2, do I have enough time to prepare the bed (through what method?)
and what transplants would you recommend?

I wanted the bed to look a little wilder/more cottage garden-y anyway, and
planted mostly wildflowers and medicinal flowers.