5 aquatic plants for a mild climate

The Nymphaea tetragona, known as the dwarf water lily, is ideal for small ponds and containers on terraces due to its small size. Its white semi-double flowers, with orange-yellow stamens, measure between 5 and 8 cm in diameter. Its dark olive-green leaves, speckled with purplish-brown, add to its charm. This plant is a real jewel to behold up close.

Originating from the northern hemisphere, the white dwarf water lily is found in Europe, Asia and North America. It thrives in calm, shallow water. This aquatic perennial has a vertical rootstock and floating leaves that are oval to elliptical. Its solitary flowers, and sometimes fragrant, can reach 8 cm in diameter. After flowering, it produces fruits underwater, releasing seeds that germinate in the sediment.

Water lilies help oxygenate the water, providing shade and shelter for fish. The Nymphaea tetragona is hardy to around -10°C. Rootstocks should be planted at a depth of 20 to 40 cm, in good garden soil, rich and free from stones. Provide them with the sunniest spot in the water feature.

The Thalia dealbata, also known as white Thalia or water canna, is an aquatic or semi-aquatic perennial, often evergreen, distinguished by its large size and mauve flower spikes in summer. It is ideal for ponds, offering a vertical and exotic touch to the garden. In fertile soil and under a mild climate, it can reach large dimensions, though its hardiness is limited.

Belonging to the Marantaceae family, the Thalia dealbata is native to the southern United States, where it grows in marshes and sunlit wetlands. This plant spreads thanks to large underground rootstocks. In summer, it produces tall flowering spikes with waxy flowers in shades ranging from white to mauve. The flowers, nectar-rich, attract bees and are followed by purple seeds. Its large oval leaves, bluish-green and covered with a whitish tomentum, appear in spring. Although evergreen in its natural habitat, Thalia dealbata becomes deciduous in colder climates.

This plant is perfect for large ornamental ponds, planted directly in the mud or in a submerged basket. It adds a unique exotic charm. Its creeping habit allows it to be used as groundcover, even in a damp rockery, provided it has enough space. It requires full sun to thrive. The Thalia dealbata can also be grown in a large tub on a terrace, with its feet in the water, and should be protected from cold in winter.

The rootstocks settle at depths of 0 to 50 cm below the water surface. Planting depth can be adjusted according to the minimum winter temperatures. The rootstocks are protected by the water depth, and withstand temperatures down to -17°C, but conversely, deeper spring coolness results in a later restart of vegetation in spring.

The Aponogeton distachyos, an exotic aquatic plant, stands out for its floating leaves and large white bracts that emit a vanilla-scented fragrance in the evening. Flowering mainly in late winter, its flowering is reminiscent of orchids and shines during the short days, offering a unique beauty suitable for all pond types, including shaded ponds where water lilies do not thrive.

Originating from South Africa and introduced to Europe in the seventeenth century, Aponogeton distachyos has naturalised in Australia, France and England. This plant, forming clumps up to 80 cm in diameter, flowers from spring to autumn, and sometimes in winter, with spikes of fragrant flowers attracting bees. The flowers, initially white, turn green as they age. The plant goes into dormancy in summer, but can continue to flower during a mild winter. Its leaves, 6 to 25 cm long, are initially submerged and then floating.

The water vanilla prefers sun but tolerates shade. It prefers freshwater and is frost-tolerant, down to -10°C. In winter, protect the rhizomes from frost. Planted in shade, it will flower from April to the first frosts. Note that koi carp are fond of this plant, so some protection may be necessary.

The fragrant Aponogeton distachyos is an excellent alternative to water lilies in areas with limited sun. Perfect for medium to large ponds, it should not be planted too close to water lilies to avoid shading them out. It can be paired with Thalia to create a vegetative cover. This plant follows the natural cycle of its country of origin, flowering in the opposite season to other plants.

The Cyperus papyrus, known as the Papyrus of ancient Egypt, is a historic plant used for papermaking. Also called paper reed, it is characterised by long stems that can exceed 2 metres, ending in vast heads of bracts forming a feathery umbrella. This spectacular perennial, the most majestic of aquatic plants in mild climates, is frost-sensitive and does not survive below -3°C. It thrives in a submerged pot, requiring a sunny spot and winter shelter.

Originating from the banks of the Nile, Cyperus papyrus once formed thick thickets along the river. Today, it is rare in its natural habitat, but widely cultivated for its ornamental appearance in temperate regions, in gardens, greenhouses or conservatories.

This exuberant plant develops numerous stems without leaves, reaching about 1.5 m in our climates. It spreads laterally without limits. In spring, each stem produces a feathery inflorescence of small cream flowers, turning brown in summer. These flowers produce seeds dispersed by the wind. Cyperus papyrus propagates by its seeds and its rhizomes, but it cannot be propagated by cuttings in water.

Ideal for banks in mild climates, Papyrus is also suitable for terraces, provided it remains in consistently damp soil. It enhances the edges of a raised terrace pond.