Myriophyllum brasiliense

The Myriophyllum brasiliense, also known as Aquatic Myriophyllum, is a partially emergent perennial for temperate ponds, with purifying and highly oxygenating properties. Its long, knotted stems emerge from the water, sometimes reaching up to 40 cm (16in) above the surface. The feathery leaves are finely divided, with a bluish-green hue above water and turning reddish in autumn. Insignificant summer flowering. This trailing plant is highly appreciated by fish and other animals inhabiting ponds.

Myriophyllum aquaticum belongs to the Haloragidaceae family. It is native to Australia, New Zealand, and South America. It now proliferates worldwide in stagnant or slow-flowing freshwater. It forms tall, knotted stems that can reach 1.80 m (6ft) (sometimes 3 or 4 m (10 or 13ft)) in height, with the ends rising well above the water. The foliage, finely divided, appears yellow-green when submerged and bluish-green when above water. The leaves are arranged in whorls around the stems, and the foliage is semi-evergreen. Tiny yellow-green flower spikes open among the submerged leaves in summer. They are attached to the axils of the aerial leaves by small peduncles. The female flowers are petal-less, while the 4 white petals of the male flowers emerge from a fused calyx of the same color. The roots anchor into the soil up to 50 cm (20in) deep.

Plant aquatic milfoil in a pond, in baskets filled with loamy, humus-rich soil, in full sun, at a depth of 1 m (3ft), under 10 to 150 cm (4 to 59in) of water. At planting, the myriophyllum needs to be weighted down as it has few roots. This plant is hardy to about -7°C (19.4°F). Install it in full sun. With good light, you will achieve a pink-purple coloration of the plant. It also shows great tolerance to pH and water softness. The emerged stems may suffer from frost but will reappear in the following spring. The stump is susceptible to freezing and it develops best in warmer waters (between 15 and 25°C (59 and 77°F)). It starts growing very early in spring (as soon as the temperature reaches 10-15°C (50-59°F)), before native plants. The young shoots may be attacked by fish that delight in them. Algae or debris in the water suffocate the leaves of this plant. When it thrives, its exceptional vigor can make it invasive. Therefore, it needs to be controlled either by placing it in a basket (when possible) or by limiting its growth by regularly removing part of the stems.

Myriophyllum brasiliense is a top-notch oxygenating and purifying plant. It has the ability to concentrate nitrogen and phosphorus. Through its filtering action, it helps stabilize the often delicate balance of a garden pond. When the size of the pond allows it, it is preferable to install two or three species of submerged plants to vary the foliage. This plant can also be used in tropical fish aquariums, but in this case, provide it with sufficient light.

Aquatic milfoil was introduced to France around 1880 as a spawning ground for certain fish. It has become a harmful plant in certain areas of our territory, which is why we are stopping the commercialization of this species considered invasive according to European Directive No. 1143/2016.