At least these panels stay green year round and don't require trimming. Some options to consider include Nolruo Artificial Hedge Boxwood Panels or the NETAP Artificial Grass Wall Panels.

The kdgarden artificial boxwood panels are faux grass wall covering that come in 6 PCS of 20 x 20. No need for watering, trimming, or fertilising, makes them ideal for low-maintenance spaces.