The City Council may, if the property owners along any street fail or refuse to plant the trees determined upon and ordered by the City Council as provided in § 12.24.010, within the time fixed by the Council for such improvement, proceed in the manner provided by law to cause such trees to be planted at the expense of the owners of the adjacent property and to cause the same to be properly cared for and cultivated, so that the trees upon such street may be harmonious and symmetrical, and shall conform to the plan adopted by the Council.
(`83 Code, § 12.24.020)