Pontederia cordata is a rhizomatous perennial aquatic plant native to the American continent. It consists of a rosette of large lance-shaped floating leaves, broad, thick and spongy, of a bright dark green color, which grow up to 50-60 cm in height. In summer it produces a decorative and showy spike of violet-blue flowers, whose central petals have a yellow spot, on a long rigid stem; flowering is usually long and may continue until the first cold autumn arrives. P. cordata alba has completely white flowers. The plants of pontederia cordata they have vigorous growth and tend to form large colonies of fleshy rhizomes; with time it is good to check the size of the colonies, to avoid that they completely fill the water basin.
As regards the correct indications for the exposure of this variety, it is good to know that the pontederia cordata prefers very bright places, preferably sunny; this species also adapts to half shade, but not to the complete shade, where flowers usually fail to bloom.
Generally this variety of plants does not fear the cold, although much depends on the way in which it is cultivated, since the roots can freeze when exposed directly to the harsh and cold climate; in places where one is exposed to cold winters it is advisable to keep the pontederies in deep water, so that the water around the roots and at the base of the leaves is not subject to frost.
This kind of aquatic plant has no particular needs regarding the soil. It is possible to grow new plants in containers filled with balanced universal soil mixed with sand.
For their optimal development it is good to place the pontederie in ponds not very deep, possibly quiet, or on the banks of ponds or small ponds; in the latter case be very careful that the soil never dries, and mulch all around the plant in the coldest months of the year, to prevent the roots from being reached by frost. In places where winters are not too harsh it is possible to cultivate the pontederies completely floating on the surface of the water.
these plants produce numerous seeds, which can be used in autumn, as soon as they are picked, and they must be made to germinate in a mixture of peat and sand in equal parts, which must be kept constantly wet. In late spring it is possible, sometimes it is appropriate, to divide the tufts of rhizomes, practicing quite large portions, each of which is provided with some leaves and some roots; new plants are planted directly. Divide only when the climate is mild and the plants have resumed vegetating, to prevent the roots, exposed to too cold a climate, to rot.
Pontederia cordata: Pests and diseases
As regards the possibility that the specimens belonging to this kind of plant, it is good to remember to pay attention to aphids and cochineal, which can easily attack and ruin the specimens of this variety. For greater safety it is possible to intervene with preventive treatments based on broad-spectrum insecticides.