WaterLilies (genus Nymphaea) are the most important representatives of this deep zone. There is a very wide range of cultivars with different flower-colours and different recommended water depths. Table 8.5 shows only a few examples. For further information Wachter (1998) is recommended. Though Water Lilies prefer meso – to eutrophic conditions, they thrive well in water poor in nutrients if they have enough space to develop a large root system. Whilst Nymphaea species and Hybrids prefer sunny conditions, Nuphar species withstand even shady sites. Most of the other deepwater plants tend to be very invasive by producing rampantly growing rhizomes either penetrating the mud (Persicaria amphibia) or floating along the water surface (Nymphoides peltata).
Rooted submerged hydrophytes can cover the pond’s bottom with spectacular carpets. It is advised to avoid the extremely competitive Elodea canadensis: this can overgrow even Water Lilies. Instead, oxygenation can be guaranteed by rootless Ceratophyllum species: these are easily removed when too prolific. Potamogeton species can spread rampently too, but species of this genus are suitable even in deep water in large ponds.
Callitriche palustris, Crassula recurva and Hottonia palustris mediate between zones 5, 4 and
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coconut fibre mat or fabric
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substrate
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coconut
8.21
Possibilities for floating islands
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