Most plants found on rocky shores are seaweeds. They’re algae, which means they can live on hard surfaces where plants with roots wouldn’t be able to survive. Instead of roots, they have special suckers called ‘holdfasts’ which cling to rock, even in big waves. They don’t have flowers, or normal stems or leaves. Seaweeds are mainly green, red or brown, depending on which wavelength of sunlight they’re trying to trap.