Ussurian watermilfoil

Ussurian watermilfoil (Myriophyllum ussuriense) belongs to the Haloragaceae family. This perennial herbaceous plant leads a fully or partially submerged lifestyle, developing in stagnant or slow-moving freshwater bodies.

The origin of this species covers regions of the Far East, including the Ussuri River basin, as well as parts of East Asia, including Japan and the Korean Peninsula. The plant prefers well-lit areas of water bodies with muddy or sandy-silty bottoms rich in organic matter.

For successful growth of the crop, a stable water temperature regime is required during the summer period, usually in the range of 18 to 25 degrees Celsius. The plant is sensitive to sudden changes in the chemical composition of water and prefers a slightly acidic or neutral environment with sufficient carbon dioxide levels.

Botanically, the species is characterized by thin stems and feathery leaves arranged in whorls. Such a structure promotes intense photosynthesis and active absorption of nutrients dissolved in the water, which makes the crop an important biological component of the aquatic ecosystem.

The economic use of watermilfoil is focused primarily on the ornamental sector. It is actively used for landscaping artificial ponds, natural pools, and aquariums, as the plant effectively oxygenates water and serves as shelter for small aquatic fauna.

The main threats to the development of Ussurian watermilfoil are sudden water pollution from domestic or industrial runoff, as well as the excessive growth of blue-green algae, which block access to sunlight.

Pests, such as larvae of certain insect species or mollusks, can damage the delicate feathery leaves of the plant at high population densities. Also, the plant can be suppressed as a result of the intensive growth of filamentous algae competing for mineral nutrition.