żółkną

In a sentence

• Liście żółkną jesienią.

  Leaves turn yellow in the fall.

  Here, 'żółkną' is used in a descriptive context to describe the natural color change of leaves.

• Czy twoje kwiaty w doniczce też żółkną?

  Are your potted flowers turning yellow?

  In this sentence, 'żółkną' is used to indicate the action of flowers losing their green color, possibly due to a health issue.

• Słońce świeci tak mocno, że trawa na polanie żółkną.

  The sun shines so strongly that the grass in the meadow is turning yellow.

  Here, 'żółkną' is describing the change in grass color due to dryness or lack of water caused by intense sunshine.