Again the Liriope m. Silvery Sunproof. This species would normally occupy a mixed plant community that contained other members including various broad leafed perennials and shrubs their roots systems occupying different volumes, intercepting the sun and energy that here powers the growth of weeds. Nature doesn’t create single species stands, except in very rare situations. Here it is up to maintenance staff to maintain this imbalance, which would need to be regularly and frequently done, but possible with considerable commitment to resources and labor. Red Clover has invaded and if left on its own will dominate. Because of the way that it roots as it spreads the longer one waits the more difficult it will be to manually remove. Chemically broadleaf weeds like this can also be difficult to kill with post-emergent herbicides. As with most weeds they are more effectively dealt with at an early stage. Here’s an interesting link to an article discussing weed control in Liriope out of Delaware Extension. Keep in mind if you read it that drought tolerant in summer wet Delaware is different than here.