Genesis 1 says God made the land produce vegetation, and so the land produced plants and trees, on the third day. Then God made mankind, and gave them all the plants and trees on earth as a source of food, on the sixth day.

But Genesis 2 says God formed the first man when “no shrub had yet appeared on the earth and no plant had yet sprung up“.

Possible explanation

Maybe God made a mistake, and the pre-human plants all died because the sun didn’t exist yet, so God had to make new ones later.