Deep Water Aquatic Plants
Apart from thethere are a number of other subjects which require growing in deep water if they are to do well. The nuphars (pond ) are the most important of these. Often confused with true waterlilies, they produce similar floating foliage but smaller like tiny brandy bottles. For the most part they are inferior to the , but will withstand a certain amount of shade and tolerate . Where such conditions prevail they provide a useful alternative.
Our native Nuphar lutea is the species most frequently encountered. A vigorous plant, it is only suitable for large pools with a depth of water in excess of 60cm. It has handsome, bright green, leathery floating leaves and bright yellow, bottle-shaped flowers with a somewhat sickly odour. Several forms exist with blossoms splashed or infused with red, but these are only a trifle more endearing than the native species.
A much better nuphar for the average garden pool is N. pumila (dwarf pond lily), a more modest version of N. lutea with flowers of sulphureous yellow. This will grow in as little as 30cm of water and is not likely to encroach upon neighbouring plants. For this reason it is an excellent subject for the rock garden pool. So is N. microphyllum, a little gem with crispy, membranous underwater foliage, tiny floating leaves and myriads of small yellow blossoms.
Aponogeton distachyus (water hawthorn) is much more showy than any of the nuphars. Although a South African native, it is absolutely hardy, producing striking black and white flowers with a delicious vanilla fragrance. These are in evidence from April until the first autumn frosts and float amongst long, dull green leaves heavily splashed and spotted with purple. Aponogeton is always an asset, being of modest growth and with a length of flowering season unequalled by any other aquatic.
Not even Nymphoides peltata (water fringe) can match the aponogeton, for although flowering until well into the autumn its first golden chalices do not appear until mid-summer. These are buttercup-like, delicately fringed, and sprinkled amongst tiny green, waterlily-like foliage which is often splashed and blotched with brown.
Brasenia schreberi (water shield) is of similar habit and has small rounded leaves and unusual, rich purple, floating blossoms during the summer.
This lovely plant is not easily cultivated, demanding a position in full sun and water of an acid persuasion. However, the enthusiastic pool owner who can fulfil its needs will be well rewarded.
Orontium aquaticum (golden club) is not so fastidious. Indeed, it is probably the most adaptable of all the deep water aquatics, prospering in damp muddy conditions or up to 45cm of water. In deeper water it always looks happier, for much of the spring and early summer thrusting up gold and white pencil-like flowers in profusion amongst attractive, glaucous, floating foliage.