Show the children a real plant. Ask them to identify what they can see. Write their ideas up on a WB or piece of paper. Pick the flower apart with the children. This is the stem, leaf, flower, roots. Identify what each part of the plant needs to help it to grow. Explain that a plant would not be able to grow without each part. Model labelling the parts of the plant. What does a plant need to help it grow? What colour should a plants leaves be if it is healthy? How do we know that a plant is unhealthy by looking at it?
Activity- children need to label a plant for me, the sheet is attached. I would encourage the children to write the parts of the flower but if they are struggling with that then they can cut the words out and stick them in the correct place.
Attached is also a ppt for you to talk through with the children.