The commission shall have authority, subject to the approval of the board of supervisors, to employ a competent landscape engineer to prepare plans for the beautification and landscaping of the area described in Section 55-11-7, and for any part thereof, and to approve and adopt plans for the beautification and landscaping of such areas that the commission may deem proper. However, as to any such beautification or landscaping, the cost of which is to be paid by said county, such adoption or approval shall be subject to the approval of the board of supervisors. The board of supervisors shall have authority to pay the expenses of preparing such plans out of their general fund or any other funds made available for the purposes of this chapter.