; but (B) is encouraged to consider, with respect to cost, schedule, product supply, overall maintenance requirements, and property usage, the planting of native plants on appropriate areas of existing or planned turfgrass and lawns, particularly unused areas, while carrying out a Federal project. (c) Contractor requirements In entering into a Federal contract, the head of a Federal agency shall— (1) include the priority and consideration requirements described in subsection (b) in the contract, to the maximum extent practicable; and (2) require that any subcontract (at any tier) of that contract include those priority and consideration requirements. (d) Update to agency-Specific design standards Not later than 270 days after the date of enactment of this Act, a Federal agency that maintains agency-specific facility design standards or that has landscape and maintenance development requirements or standards shall update those requirements and standards in accordance with subsections (b) and (c). (e) CEQ Guidance Not later than 180 days after the date of enactment of this Act, and every 2 years thereafter, the Chair of the Council on Environmental Quality shall distribute to Federal agencies guidance on— (1) the use of native plants in Federal projects