Water Weed ID: Submerged Plants, Part 1

Every waterfront dweller knows that identifying water weeds is the first step to understanding and controlling aquatic vegetation. In the first installment of our “Water Weed ID: Submerged Plants” series, we’ll walk you through some of the most common submerged weeds found in North American waters.

Milfoil (Myriophyllum)
Milfoil leaves are whorled in groups of four, and each leaf is divided into many thread-like leaflets extending from a central rib. It is easily identified by the tangled mats it forms on the water’s surface. Seed heads develop in mid to late season and may extend above the water surface. You can treat for milfoil anytime the weeds are actively growing.

Source: www.dnr.wi.gov

Parrot Feather (Myriophyllum Brasiliense)
Also a type of milfoil, parrot feather leaves are whorled in groups of four to six. Each leaf is divided into eighteen pairs of thread-like segments resembling a feather. This species differs from other milfoils by having its foliage partially out of the water. Submerged foliage is bright green.

Bladderwort (Utricularia)
Bladderwort can be identified by its finely divided leaves scattered along the stem with numerous bladder-like structures on leaves. Its stems have many branches and are densely leafy at the tips. Flowers are yellow and rise above the water surface when mature.
 
Hydrilla (Hydrilla Verticillata)
Similar to elodea, hydrilla has leaves are whorled in groups of three or more. Leaves have a serrated edge with two to three pointed spines on the midrib of the underside. Whorls of leaves are compact near the growing tips, and spacing between whorls increases further down the stem.

Source: www.adn.com

Elodea (Elodea Canadensis)
Similar to hydrilla, Elodea leaves are whorled in groups of three, have smooth edges and are com compact near the growing tips. Spacing between whorls increases further down the stem.

Want to keep learning about submerged weeds? Read more here and here.