Thanks! There is a Bush nearby. It only flowers in the spring.

If you remove the seed pods before they turn brown and split open, it will prevent any more from appearing. Takes a little bit of time, but we'll worth it. Those Rose of Sharons seed all over the place. The most practical thing to do would be to nip off faded flowers along with the forming seedheads as they appear. That way you prevent future unwanted seedlings, and keep the shrub looking good at the same time.

Rather than using chemicals, the seedlings are very easy to pull up, roots and all.

You won't do the lawn much good if you smother it. Surely the lawn mower will deal with these?

With these Rose of Sharon seedlings all you need do is mow and as they try to grow and get a bit taller and the leaves are closer to the mowers height and get cut off, therefore denying the plant the nutrients it needs to grow more, they will die. There is no need to spray plant poisons, which will harm your environment, around.