"May the flowers grow well" means that flowers and plants can thrive and be beautiful. We can understand that we hope all plants can thrive and be full of vitality.
"People grow stronger" means that people should be healthy and strong. This is a good wish for the health of others.
"The moon is always round" means that I hope the moon will always be perfect without any obstacles. This is a symbol of harmony and smoothness. I hope everything goes well.