canescent
adjective
ca·nes·cent kə-ˈne-sᵊnt 
ka-
: growing white, whitish, or hoary
especially : having a fine grayish-white pubescence
canescent leaves
Word History
Etymology
Latin canescent-, canescens, present participle of canescere, inchoative of canēre to be gray, be white, from canus white, hoary — more at hare
First Known Use
circa 1775, in the meaning defined above