fadeless
adjective
- unfading (exempt from fading/decay)
Wiktionary
adj
Etymology: From fade + -less.
- Not fading; eternal
“Stranger! new flowers in our vales are seen, With a dazzling eye, and a fadeless green,—”
“Palms of vict'ry thou shall bear, / And a crown of fadeless light / Will be given thee to wear, / And a robe of spotless white.”