Hello, I have a bed at the end of my driveway that currently has a yew bush and some yellow daylillies. The area around the edge of the bed gets extremely weedy, and mulch does not sufficiently keep the weeds at bay. I just finished pulling all of the weeds and would like to plant some perennials to cover the area. What would you suggest I plant for (1) around the edges of the bed, and (2) in the center of the bed to complement the daylillies?

The bed is in full sun. I am in Zone 7. The plants need to be pretty hardy once established because the bed is in an inconvenient spot to water frequently. They must also either not creep out over the surrounding sidewalk, or they need to be ok with being trimmed back regularly.

Thanks for any suggestions!