The idea is from Haydn, but this time "The Seasons".
The text is also from "The Seasons". (Some would argue the German text is prior, but the work depends on an English poem, then very popular, by Thomson). The verse continues "and from her wintry grave Bid drowsy Nature rise." So the green figure is Nature rising. This is sung by the female chorus. It should not be forgotten that the male chorus is about to counter "As yet the year is unconfirmed" and take us back to contemplating frosts!