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Aquatic Plant Ailments

By Rupert Foxton-Smythe

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Discover common ailments that can affect water-lilies and marginal plants, including fungus diseases and fascinating phenomena. Read more to learn how to address these issues.

TL;DR

Water-lilies and marginal plants can suffer from ailments such as fungus disease and fasciation.

  • Fungus disease of the genus Cercosporae can cause spots on the leaves of water-lilies, which become dry and crumpled. Bordeaux mixture can be sprayed on the leaves every other day to remedy this.
  • Fasciation is a phenomenon where water-lilies produce a larger number of tiny leaves instead of normal-sized leaves. To address this, remove any normal-looking shoots and plant them separately.

So much for the actual pond; water-lilies and marginal plants are susceptible to few ailments. Nymphaeas may sometimes suffer from a fungus disease of the genus Cercosporae. This is comparatively rare, but when the fungus is present, spots will develop on the leaves which became dry and crumpled. A light spraying of Bordeaux mixture, applied every other day at half the strength directed for other plants, is the only remedy. The affected leaves should, of course, be removed.

But do not mistake the natural decay of leaves for this fungus. If healthy leaves are rising to the surface and developing as others are dying off, then this is only evidence of the natural cycle of events. And, of course, once autumn frosts have arrived you can expect the Nymphaeas to die back quickly.

Fasciation in Water Lilies

A peculiarity of some water-lilies is the phenomenon known as fasciation. An individual plant may grow and flower normally for a number of years. Then, for no apparent reason, it ceases to bloom and instead of producing leaves of usual size, it throws up a much larger number of tiny leaves. If you lift the plant you will discover, instead of just a few separate and well-defined growing points, a jungle of leaves and shoots growing all over the tuber.

Fasciation is rare, but when it occurs there is only one solution. Remove any eyes or shoots that appear normal. These can be planted and should grow into ordinary tubers which will flower and produce leaves of the usual size. The original tuber can be discarded.

Reverting to Type in Marginal Plants

Reverting to type is a tendency that you may notice with some of your variegated marginals. In amongst the variegated foliage plain green stems may develop. Given time, the whole plant may revert to the plain colour of its ancestors and you will have lost the variegated species with which you began. The only thing you can do is cut out the plain stems as they arise and hope that the rest of the plant will remain true to type.

The fact that the variegation on the leaves of his pseuda-corus variegatus, for example, may lose some of their lustre, the green and bright creamy stems taking on a duller appearanceat the end of summer, is not evidence of reverting to type, but only of the ageing process of the leaves. Should any straight leaves appear on Juncus effusus spiralis, they also should be ruthlessly cut out.

So much for the actual pond; water-lilies and marginal plants are susceptible to few ailments.

More Information on Aquatic Plant Ailments

Aquatic plants, such as water-lilies and marginal plants, can encounter various ailments that can affect their growth and health. One common issue is a fungus disease called Cercosporae, which can affect the leaves of water-lilies. When infected, spots develop on the leaves, causing them to become dry and crumpled. To address this problem, a light spraying of Bordeaux mixture can be applied every other day at a reduced strength compared to other plants. It's important to remove the affected leaves to prevent the spread of the fungus. However, it's crucial not to mistake the natural decay of leaves for this fungus. Healthy leaves rising to the surface while others are dying off is a normal cycle of events. Additionally, as autumn frosts arrive, the Nymphaeas will naturally die back. Another peculiar phenomenon that can occur with water-lilies is fasciation. This occurs when a plant, after several years of normal growth and flowering, suddenly ceases to bloom and produces an increased number of tiny leaves instead of the usual-sized leaves. If you lift the plant, you'll notice an abundance of leaves and shoots growing over the tuber instead of well-defined growing points. The best solution for fasciation is to remove any normal-looking eyes or shoots and plant them separately. These can develop into ordinary tubers that will produce normal-sized leaves and flowers, while the original tuber can be discarded. In some cases, variegated marginals may exhibit a tendency called reverting to type. This means that among the variegated foliage, plain green stems may develop. If left unchecked, the entire plant may eventually lose its variegation and revert to the plain color of its ancestors. To prevent this, it's important to regularly remove the plain stems as they arise and hope that the rest of the plant remains true to its variegated type. Keep in mind that the natural aging process of leaves, such as the variegation becoming duller at the end of summer, is not evidence of reverting to type. Understanding and addressing these ailments can help ensure the health and vitality of aquatic plants in ponds, pools, and water gardens.

About the author

Rupert Foxton-Smythe

Rupert Foxton-Smythe is a seasoned horticulturist and avid plant enthusiast with over three decades of experience in the field of botany. As a leading expert at Houseplant Guru, Rupert brings a wealth of knowledge and a deep passion for all things green.

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