Myriophyllum spicatum

Eurasian watermilfoil has an evergreen to an annual pattern of growth (depending on local conditions). It is a submerged aquatic, rooted, perennial, herbaceous plant, growing 6 to 20 feet long, or much longer, and frequently forming dense mats. Its small, yellow to pinkish flowers are clustered at the tips of the stems and located above the water's surface, often remaining above the surface until pollination is complete, then resubmerging. The flowers have either male or female parts, with both arranged along a reddish spike at the ends of stems. On the spike, the male flowers are located above the female flowers, which are pollinated by wind, and less common by insects.

Eurasian watermilfoil is a submerged plant tolerating a wide range of water conditions, including still and flowing waters, spring water, and the brackish and saline (salty) water of tidal creeks and bays. It appears to prefer lakes, ponds, and slow-moving rivers, and streams, but can also quickly in fast-moving water. It requires high light locations and can grow in a broad range of temperatures. It grows best on fine-textured, inorganic sediments, and relatively poorly on highly organic sediments.

If drought seems to be the cause of leaf senescence for a plant, please make a comment about it for that observation.

This species has separate male and female flowers. If you know whether the flowers you are observing are male or female (or both), please make a comment about it for that observation.