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Pontederia crassipes

Pontederia crassipes · Pontederiaceae

The gardener's calendar

The right move for September

Ideal time to plant pontederia crassipes: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.

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ID card

Common name
Water Hyacinth
Family
Pontederiaceae
Type
Floating aquatic plant
Flowering
July to September
Flower color
Lavender violet-blue
Mature size
0.3 to 0.6 m in height
Growth
Very fast
Origin
South America (Amazon basin)

Care

Watering and immersion

The Water Hyacinth is entirely aquatic: it must float or be immersed in a pond, lake, or aquarium with a minimum depth of 30 cm. Keep the water calm and still, at moderate temperature (15–25 °C). If the water becomes polluted or stagnant for too long, replace part of the water regularly to prevent asphyxiation.

Light and exposure

Place the plant in full sun or partial shade; it will flower more abundantly with 5 to 6 hours of direct sunlight daily. Insufficient light reduces flowering and lengthens the petioles. In very hot zones, afternoon shade can prevent desiccation.

Fertilization

Enrich the pond water with a balanced aquatic plant fertilizer (NPK) or apply nitrogen-rich nutrients once or twice a month during the growing season (May to September). Water that is too nutrient-rich promotes excessive proliferation; stay moderate.

Aquatic environment

The Water Hyacinth requires no substrate: it floats freely or anchors weakly to the bottom of a shallow pond. A substrate rich in organic matter (silt, aquatic soil) can improve rooting if it is semi-immersed, but is not necessary.

Pests and diseases

Watch for aphids and spider mites during warm periods. Yellowing leaves indicate nutrient deficiency or polluted water. If you notice root or petiole rot, reduce plant density and improve water circulation.

Pruning and control

Regularly remove dead or damaged leaves to maintain appearance and prevent disease. Control growth by removing excess plantlets, as the Water Hyacinth reproduces very rapidly and can choke a pond in just a few weeks.

Did you know?

The Water Hyacinth has become one of the most dreaded invasive aquatic plants in the world: it covers entire lakes in Africa, Asia, and South America, threatening ecosystems and waterways. Paradoxically, in Southeast Asia and Africa, it is cultivated for its water purification qualities and is even consumed by livestock. Its extraordinary reproductive capacity (a single plant can multiply by 500 in just three months) makes it both a marvel and an ecological curse.

Where to buy it

Best planted in spring or autumn, away from frost and heatwaves. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September, October.

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Tips generated and checked by Viridia — adapt them to your local climate.