that borders upon a legal highway upon which State reward has not
been paid, shall have the right to plant said approved ornamental,
nut bearing, or other food producing trees along the line of said
highway adjoining said land, and shall receive annually a credit of
five cents upon his highway repair tax for each tree so planted by
him and growing in good order, not less than six feet in height
when planted and not less than twenty and not more than forty feet
apart. All of said trees and their products shall belong to the
owner of said land: Provided, that no bounty shall be paid or
deduction allowed under the provision of this section upon any one
tree or row of trees for a longer period than five years. The owner
of such trees shall have the care thereof and shall have the duty
and responsibility for the trimming, spraying and cultivation
thereof.