Waterlilies, if left unchecked, can and will multiply by both seeds and rhizomes. They can take over any body of water.
Lizards Tail.
Equisetum hymale, or horsetail reed, is a
beautiful but aggressive evergreen plant
that has been found in fossilized remains
and can grow from 2 to 4 feet tall.
Pickerel Rush.
Parrot's Feather.
Umbrella Palm.
Water Celery,
Water Clover,
Water Poppy.
Yellow Flag Iris.