Blyxa japonica

Egeria densa is a robust aquatic perennial characterized by its sprawling, branching stems that can grow up to 90 cm in length. The stems are adorned with whorls of slender, linear leaves that extend along their length. When the stems reach the water's surface, they create dense mats. In late spring, and occasionally in autumn, small white flowers emerge on delicate stems, rising slightly above the water's surface. Commonly marketed as an aquarium plant, it has the potential to become invasive if introduced to non-aquatic environments.

Egeria densa

Egeria najas

Elodea consists of perennial aquatic plants that grow underwater, characterized by upright, spreading stems and vibrant green leaves arranged in groups of three. Small, individual flowers emerge from the leaf axils.

Elodea

Elodea callitrichoides

Elodea canadensis is classified as an invasive non-native species under Schedule 9 of The Wildlife (Northern Ireland) Order (1985), and its sale is prohibited. For cultivation information, refer to the notes below. This aquatic perennial is semi-evergreen and features a group of submerged, branching stems adorned with tightly arranged, curved dark green leaves.

Elodea canadensis

Elodea nuttallii is classified as an invasive non-native species under Schedule 9 of The Wildlife (Northern Ireland) Order (1985), and its sale is prohibited. Refer to the cultivation notes for additional information.

Elodea nuttallii

Halophila ovalis

Hydrilla verticillata

Hydrocharis consists of aquatic perennials that can grow either submerged or floating. They feature smooth, rounded foliage and produce white flowers with three petals during the summer months.

Hydrocharis

Hydrocharis morsus-ranae is a perennial aquatic plant that floats on water surfaces. It features rounded leaves that measure approximately 3 cm in diameter. The plant produces white flowers, each 2 to 3 cm wide, adorned with a yellow marking on every petal.

Hydrocharis morsus-ranae

Lagarosiphon consists of semi-evergreen, submerged aquatic perennials that produce a cluster of branched stems. These stems are covered with spirally arranged, linear-lanceolate leaves and bear small white or pink flowers during the summer months.

Lagarosiphon

Lagarosiphon major is classified as an invasive, non-native species under Schedule 9 of the UK Wildlife & Countryside Act, making its sale illegal. Refer to cultivation notes for additional information. This aquatic perennial features tightly arranged, bent dark green leaves and produces small, tubular pinkish flowers during the summer months.

Lagarosiphon major

Limnobium

Limnobium laevigatum

Limnobium spongia

Najas

Najas flexilis

Najas guadalupensis subsp. olivacea

Najas marina

Najas marina subsp. intermedia

Najas minor

Najas tenuissima

Stratiotes are robust, dioecious aquatic perennials that grow submerged. They develop stalkless rosettes featuring toothed, sword-like foliage. The flowers are either white or pinkish, with females appearing singly and males in small groups.

Stratiotes

Stratiotes aloides is a perennial aquatic plant that develops rosettes composed of slender, pointed leaves reaching lengths of up to 45 cm. During the summer months, it produces white flowers measuring approximately 3 cm in diameter.

Hydrocharitaceae