Bark mulch suppresses weeds by blocking light that seeds need to germinate, but it doesn't completely prevent weeds. It also helps retains moisture in the soil and keeps plant roots cool in hot weather. Bark mulch resists compaction, it doesn't blow away and it provides an attractive finish to newly planted areas.

Is bark good for stopping weeds?

A thick layer of home-made, well-rotted compost or specially bought loose organic mulch such as bark chips, stops weeds by providing a barrier through which light cannot pass. Put down the mulch while the soil is moist and before the first weeds begin to emerge in spring.

Can weeds grow through bark mulch?

Weeds can grow through mulch since their seeds can be in the soil or be brought in the bed by birds. Given their toughness, they will force their way through most mulching materials such as pine needles or even bark chips. They could even start growing way before the main plants in the bed.