Water lilies reproduce both by way of seeds and by the spreading of their tenacious roots, or rhizomes. Though lily pads spread relatively slowly, they can eventually take over entire shorelines and are considered invasive in some areas. Water lilies and their surface lily pads can blanket areas of water as deep as six feet. A single rhizome can reproduce and grow to cover an area 15 feet in diameter in as little as 15 years. When spread to non-native habitats, water lilies can shade the water and make it too cold for native species of fish and plants. Water lilies may also compete with native plants for nutrients.