Curly Leaf Pondweed
Habitat: Curly-leaf pondweed is found in the submersed plant community. Generally preferring soft sediments, it grows in waters that are shallow or deep, still or flowing. Curly-leaf pondweed is a hardy plant that thrives where many other aquatic plants do not, for example in waters that are shaded, disturbed, polluted, or turbid.
Description: Curly-leaf pondweed leaves are submersed, arranged alternately, reddish-green, somewhat translucent, ruffled (like a lasagna noodle), and have finely serrated edges. The leaves are 4-10 cm long, and 5-10 mm wide. Slightly fattened stems emerge from slender rhizomes and sprouting turions, often branching profusely as they grow, giving the plants a bushy appearance. Mature stems may be several metres in length. Flower spikes appear above the surface of the water from June through September. The small flowers are tightly arranged at the end of a slender (often curving) stalk measuring about 7 cm in length.
Origin and Range: Curly-leaf pondweed is native to Eurasia. It was introduced to North America during the mid-1800s, and has since spread throughout most of the United States including all New England states. In Canada, it can be found in British Columbia, Alberta, Saskatchewan, Ontario and Quebec. It was recently found in a pond in southern New Brunswick.
Annual Cycle: Curly-leaf pondweed, an aquatic perennial, is adapted to growing in cool conditions. Plants sprout from rhizomes and turions (or winter buds) in the fall and grow through winter, reaching maturity relatively early in the season (late spring through early summer). Flowers and turions are produced during the growing season and plants generally begin breaking up by mid-July. The turions scatter with the plant fragments and drop to the sediments, where they lie dormant until the water begins to cool again in the fall.
Look Alikes: Curly-leaf pondweed may be confused with other native pondweeds; many of which have both emergent and submerged
leaves. Curly-leaf pondweed has only submerged leaves. Other pondweeds also lack the tiny but visible serrations along the edges of the leaves. Its finely ruffled leaves help to distinguish it from all other pondweeds in our region.
Impacts: Curly-leaf pondweed’s tolerance of low light and temperature conditions allows it to grow sooner than native plants in the spring. It forms dense surface mats that can impede recreational activities such as boating, swimming, and fishing. When it dies off in mid-summer it may create anoxic conditions and increases nutrient content that can cause harmful algal blooms.