Water Hyacinth Disease


What a delight to spy perky water hyacinth floating on your pond. In optimum conditions, these colorful aquatic flowers bloom profusely during the summer months. If disease strikes water hyacinth, though, flower production may be compromised. It is important to quickly identify water hyacinth disease and prevent its spread.

Root Rot

  • There are a variety of signs that water hyacinth have root rot. According to Colorado State University, warnings include failure to produce new growth, die-back, wilting and yellowing of leaves, dark brown or black roots with no white roots or root tips, and roots that are squishy. The outer layer on the roots may also strip away easily, leaving just the interior of the roots exposed.

Fungal Disease

  • Indications of fungal disease in water hyacinth include dead spots on the top of leaves which have white fungus on the undersides. Fungus can also present itself as teardrop-shaped brown dead spots. Such spots have dark brown margins, the centers of which are covered with white and black fungal growth.


  • Pathogens on water hyacinth can cause dead spots on the leaves and stems, according to the University of Florida. Such spots are usually pale with surrounding darker markings. Sometimes the spots resemble teardrops which eventually cause entire leaves to die. If the infection is severe enough, plants may sink and decompose.

Potential Causes

  • Water hyacinth disease can be caused by a variety of factors, including insufficient oxygen in the water, inappropriate water depth or being put in the water too early in the season.


  • To prevent the spread of disease among water hyacinth, remove affected plants immediately. Then monitor remaining plants for disease. Before introducing new plants, correct any problems such as inadequate oxygen in the water.

General Prevention Tips

  • Follow good cultural practices with your aquatic garden and you are more likely to prevent water hyacinth disease. Inspect new plants carefully before adding them to your pond. The foliage should be healthy and the roots firm and white. Make sure the plants have enough sun and avoid overcrowding so that air circulation is sufficient. Because water hyacinth is a South American plant, it is important to wait until water temperatures have reached 70 degrees during the day and stay above 50 degrees at night before placing hyacinth in your pond.


  • Although water hyacinths are a favorite water garden staple, they can be invasive in certain areas of the country.

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