Complex sentence: The iris can have up to 5--8 leaves, which are greyish-green, or pale green and slightly glaucescent, they can grow up to between long, and between 0.8 and 2 cm wide.
Split into simpler sentences: The iris can have up to 5--8 leaves, which are greyish-green or pale green and slightly glaucescent. They can grow up to between long, and between 0.8 and 2 cm wide.