A: I can usually find a way to reconcile marital differences in the garden but not this time. Plastic groundcover is bad. It prevents the free flow of moisture, nutrients, and oxygen up and down in the soil. It hurts trees when spread underneath and covered with mulch. If the scheme is to plant annuals through the mulch to prevent weeds, the same caution applies. In my experience, perennial weeds like bermudagrass and nutgrass can grow right through plastic. Be gracious and offer him tea and cookies when he finishes pulling it up.