What Curly-leaved pondweed does to the habitat

Crispy-leaved pondweed forms thick carpets just below the water surface. You can imagine what that does to boating, swimming and fishing. And property values along the shore.

By forming early, even under winter ice, the colony gets a head start on all others. It dies back mid summer leaving oxygen absorbing decaying matter when the oxygen levels are at their lowest.

In can be spread easily by people emptying their home aquariums into the water supply.

Management

Crispy-leaved pondweed will not tolerate lack of light, so an opaque tarp over the area will kill it. Do it early before the buds form and native species are still dormant.

Since the roots are not deep, an aquatic rake could be used to remove the plants. Be sure to take them out of the water and bag them as they will re-sprout.

Some buy a chemical that makes the water dark to starve it of light. Others opt for herbicides that are designed to work in ponds and lakes, such as floridone or endothall.

DESCRIPTION

Botanical Glossary

Potamogeton crispus is a submersed aquatic perennial that can reach 30-80 cm (1-2.5 ft.) in length. The turions of this plant are spindle-shaped, measure 1.5-3 cm (0.5-1 in.) and can be located terminal or axillary. The stems of this plant are flattened. There are two ranks of sessile leaves that are arranged spirally. The leaves are linear-oblong in shape, measuring 3-8 cm (1-3 in.) long and 5-12 mm (0.2-0.5 in.) wide. The leaf margins are undulate and the apex of the leaf is obtuse. The stipules of the leaf are small, thin and paper-like, and disintegrate early. The peduncles are 2-5 cm (0.75-2 in.) in length and can be recurved when the plant is in fruit. The spike is dense and measures 1-2 cm (0.4-0.75 in.) in length. The body of the red to reddish-brown achene is ovoid and measures 3 mm (0.1 in.). The achene has 3 keels, with the middle keel having a small tooth projecting out from the base. The beak of the achene is conic and erect, measuring 2-2.5 mm (0.1 in.). This plant has an unusual life history. It flowers and fruits in the late spring to early summer. The plant then dies, leaving only fruits and turions (vegetative reproductive structures) to survive the summer. The turions produce new plants in the late summer or fall, leaving small plants to overwinter, sometimes even under ice. Page References Crow & Hellquist 43, Fernald 71, Flora of North America 48, Gleason & Cronquist 642, Holmgren 609, Magee & Ahles 118.