The leaves start off green but turn red later.

树叶起先是绿色，到后来会变红。

《牛津词典》

Maple leaves turn red in autumn.

枫叶在秋天变红了。

youdao

I am so afraid of speaking in the public that I would turn red whenever I appear on a stage.

我非常害怕在公众场合说话，以至于每次我站上台，我的脸都会变红。

youdao

The leaves turn colors of red and gold and then die, falling to the ground.

VOA: special.2009.11.09

They may have a high body temperature and some areas of skin may turn red.

VOA: special.2009.05.26

In fact, they get green tomatoes sprayed with ethylene gas to make them turn red.

FORBES: Magazine Article

The phytochrome can then be exposed to a different shade of red light to turn the gene off.

FORBES: Cyborg Yeast Have Their Genes Controlled By Computer

"First, modern maize pollen grains are larger and turn red when stain is applied, whereas ancient grains do not, " they said.

BBC: Maize was key in early Andean civilisation, study shows