紅葉 こうよう
kōyō

Noun
Suru Verb

1. leaves turning red (in autumn); red leaves; autumn colours; fall colors

Intransitive
Related to 黄葉
にわ がすっかり紅葉 こうようしました。
niwano kiga sukkari kōyō shimashita.
The leaves of the trees in the garden have turned completely red.