Grasses, native wild flowers and shallow-rooted ground covers are the best choices for vegetation over the treatment field. There should be no trees planted within 10 ft. of any part of the treatment field to prevent damage to the system from root infiltration. Avoid planting water loving plants and trees (willows, bamboo, etc.) and gardens for human consumption near the drain field. Also, adding too much additional soil material over the drain field could potentially suffocate the system if it is not vented.