Zoöp Observations: Water HawthornZoöp Observations: Water Hawthorn

In October and November, when most other aquatic plants have already withered or disappeared, the water hawthorn (Aponogeton distachyos) experiences its second bloom. That is when it is most visible. It also blooms in April and May, but as many other aquatic plants do the same, the water hawthorn is much less noticeable. Between the spring and autumn blooms, the oval floating leaves disappear and the plant lives a hidden existence under water. Because of its double bloom, water hawthorn has become a favorite of many pond enthusiasts over the last twenty years.

This aquatic plant originates from South Africa, where it is also called Cape pond weed, or waterblommetjie. Since 2006, the plant has also been observed in the wild in the Netherlands, mainly in canals and open waters in and around urban areas. So far the plant does not seem to be particularly invasive. Dutch winters are a bit too cold; specimens in shallow ponds and open waters often freeze to death. However, should climate change cause Dutch winters to warm up, this aquatic plant could turn into a pest. That's already the case in other parts of the world, such as southeast Australia, and New Zealand.

The striking white flowers with black dots grow on a forked spike and give off a vanilla-like scent. The oval leaves are edible: they are a crucial ingredient in a dish that goes back to the time of Jan van Riebeeck. The dish, waterblommetjies bredie, is a stew made of lamb, onions, potatoes, and the blanched leaves of this aquatic plant.

It's uncertain whether we'll see the Water Hawthorn return to the ponds of The New Institute next year. It strongly depends on the winter ahead of us.