Our Aquatic Weed Guide

Aquatic weeds are plants that grow in water or wetland environments and can often become invasive, causing ecological and economic issues. Some common aquatic weeds found in the UK include:

Canadian Pondweed (Elodea Canadensis): This submerged plant is known for its rapid growth and ability to form dense mats, which can choke water bodies and disrupt native ecosystems.

Appearance: Canadian pondweed has long, slender, and branching stems that can reach lengths of up to several meters. The stems are usually green and have a slightly reddish hue in some cases. The plant is entirely submerged, with its leaves and flowers growing entirely underwater.
Leaves: The leaves of Canadian pondweed are arranged in whorls (a circle of three or more leaves arising from the same point on the stem). Each leaf is lance-shaped and has a pointed tip. The leaves are smooth and slightly translucent, giving them a delicate appearance.

Nuttall's Waterweed (Elodea Nuttallii): Another non-native invasive species that is similar to Canadian waterweed and can outcompete native aquatic plants.

Appearance: Nuttall's waterweed has long, slender, and branching stems that can grow to several meters in length. The stems are typically olive green or reddish-brown in colour. Like other submerged aquatic plants, the majority of the plant's structure is underwater.
Leaves: The leaves of Nuttall's waterweed are arranged in whorls around the stem, usually in groups of three, but occasionally in fours. Each leaf is linear or lance-shaped and has a finely serrated margin. The leaves are slightly translucent and have a greenish hue.

New Zealand Pygmyweed (Crassula helmsii): Has become an invasive species in the UK. It is also commonly referred to as Australian swamp stonecrop or New Zealand swamp stonecrop.

Appearance: It typically grows in dense, tangled mats on the surface of water bodies or in wetlands. The plant's stems are slender and can grow up to 30 centimetres (12 inches) in length, it forms dense clusters of small, succulent leaves along the stems.
Leaves: The leaves are fleshy, elliptical to oblong, and arranged in opposite pairs along the stems, typically about 3 to 6 millimetres long and 1 to 2 millimetres wide.
The leaves are glossy green in colour, they are thick and fleshy, which helps the plant retain water and thrive in aquatic or wetland habitats. The leaves may turn reddish or brownish when the plant is under stress or during cold temperatures.

Broad-leaved pondweed (Potamogeton natans): Is a native aquatic plant found in various regions of Europe, including the UK. It is a submerged perennial plant that is well-adapted to freshwater habitats, particularly slow-moving or still waters like ponds, lakes, and slow-flowing rivers. As the name suggests, this aquatic plant is characterized by its broad leaves, which are a key identifying feature.

Appearance: As the name suggests, broad-leaved pondweed has broad, oval to lance-shaped leaves that are typically 4-8 cm long and 1-2 cm wide. The leaves have a glossy, dark green colour and are arranged alternately along the stems.

Floating Pennywort (Hydrocotyle ranunculoides): An invasive floating plant with rapid growth that can quickly cover water surfaces, affecting water flow and light penetration, leading to a negative impact on native species.

Appearance: Floating pennywort is a perennial herbaceous plant that grows on the water's surface. It has creeping stems that can extend several meters across the water, forming dense floating mats. The stems are round and fleshy, with nodes that give rise to roots.
Leaves: The leaves of floating pennywort are round or kidney-shaped, with scalloped edges and a glossy green colour. The leaves are borne on long petioles, giving them a floating appearance on the water surface.

Hornwort (Ceratophyllum demersum): An aquatic plant species commonly found in freshwater habitats around the world. It is one of the most widespread and versatile aquatic plants, known for its ability to thrive in various water conditions

Appearance: Hornwort is a submerged, free-floating plant. It has long, flexible, and branching stems that can reach several feet in length. The stems are covered in whorls of needle-like, dark green, or reddish-green leaves, which give the plant a feathery appearance.

Curled pondweed (Potamogeton crispus): is an aquatic plant species commonly found in freshwater habitats such as ponds, lakes, slow-moving rivers, and ditches. Curled pondweed gets its name from the distinct curling or wavy edges of its leaves.

Appearance: Curled pondweed has long, slender stems that can grow up to several meters in length. The leaves are elongated and lance-shaped with wavy or curled edges, giving them a distinct appearance. The leaves are usually dark green in colour and have a smooth texture.

Curly Waterweed (Lagarosiphon major): It is a submerged, free-floating perennial plant that is commonly found in lakes and ponds. Due to the fragments it produces this is an incredible invasive and hardy weed.

Appearance: Lagarosiphon major has long, slender stems that can grow up to several meters in length. The stems are covered in whorls of bright green, feathery leaves that are arranged in groups of four to eight around the stem.

Spiked Water Milfoil (Myriophyllum Spicatum): As an invasive species, spiked water milfoil can cause significant ecological problems. It tends to form dense underwater mats, which can outcompete and displace native aquatic plants. This leads to alterations in aquatic ecosystems, affecting the food web, fish habitat, and water quality.

Appearance: Spiked water milfoil is a submersed aquatic plant with feathery, finely divided leaves that are arranged in whorls around the stem. The plant can grow in a wide range of aquatic habitats, such as lakes, ponds, rivers, and streams. It can thrive in both standing water and slow-moving currents.

Parrots Feather (Myriophyllum aquaticum): As an aquatic invasive plant, Parrot's Feather can spread rapidly and outcompete native aquatic plants, leading to ecological disruptions. It forms dense mats on the water surface, limiting sunlight penetration and reducing oxygen levels, which can harm fish and other aquatic organisms.

Appearance: its feathery, bright green leaves that resemble a parrot's plumage, hence the name. Parrot's Feather is known for its rapid growth.

Mares Tail (Equisetum arvense): Is a perennial herbaceous plant belonging to the Equisetaceae family. It is one of the surviving descendants of ancient plants that thrived millions of years ago. It is known for its distinctive appearance and unique reproductive structures.

Appearance: Mares tail has a very distinct and recognisable appearance. It consists of long, hollow, and jointed stems that resemble the tail of a horse, hence the name "horsetail." The stems are green and have a rough texture due to the presence of silica in their cell walls.

If you need help identifying the aquatic weed in your water body, or need solutions on how to maintain the weed get in contact with Simply Aquatic today by emailing info@simplyaquatic.co.uk or using our contact form below.