Strike a balance between plants and the surface area of the pond; plants should cover approximately 65 percent of the surface area. Also pay attention to depth when you are planting your aquatic plants. With new plantings, initially place the pot just below the surface and gradually lower it as the plant grows. Once the plant is established, the pot can remain at the desired depth. Planting too high will cause hardy plants to freeze in the winter; too low will prevent young plants from receiving enough sunlight. Waterlilies prefer to be planted no less than 4 inches and no more than 18 inches below the surface; lotus should be between 6 and 18 inches below the surface.