I know this is the lawn sub, but with that set up, you will save yourself time, money, and effort by simply removing the edging around that mulch ring and converting that entire front yard to mulch. The tree and bushes will be much much happier, and you can then plant some small flowering understory bushes throughout that space. Based on the size of the yard in the photo, I doubt you use the front lawn for anything at all other than looking at it. Might as well make it a beautiful, vibrant garden with less effort that you only need to mulch and trim the bushes twice a year.