Nouns

(n)perennial(botany) a plant lasting for three seasons or more

Adjectives

(a)perenniallasting three seasons or more“the common buttercup is a popular perennial plant”
(s)perenniallasting an indefinitely long time; suggesting self-renewal“perennial happiness”
(s)perennial, recurrent, repeatedrecurring again and again“perennial efforts to stipulate the requirements”