What are Aquatic Plants?
Description. Any plants that grow wholly or mainly in water. Almost all are herbaceous perennials. There are hardy, half-hardy, and tender varieties. The first can be grown outdoors all the year; the second should have protection from frost in the winter; the third are suitable for cultivation only in indoor aquariums with warm water.
Soil and Situation. Most aquatics are sun-loving plants and for this reason ornamental pools should, if possible, be in the open, not under the shade of large trees. A few plants will grow in the water alone without soil, but the majority must have suitable. Medium to heavy loam is best. Manure and fertilizers should not be used for fear of polluting the water. Spread soil to a depth of about 6 in. (more, if possible) over the bottom of the pool and cover with 1 in. of clean sand or gravel. Less depth is required in an aquarium. Alternatively, place in mounds with fine-meshed wire netting to hold it in place, or in plastic baskets or . Depth of water varies from 3 ft. for some of the strongest-growing to 3 in. for many marginal plants.
Planting, Plants with normaland crowns, e.g. water lilies, rushes, reed maces, etc., can be planted exactly like herbaceous perennials, if water can be emptied from the pool. If not, they are best planted in plastic baskets or pots and sunk in . A simple way of planting oxygenating plants, i.e. plants which supply oxygen to the water, is to tie a stone to the bottom of each, and sink in position. No plants should be put into ice-cold water or water drawn direct from the main. It should be allowed to stand for a while to be warmed by the sun and acted upon by the atmosphere. It is better to fill pools gradually as plants grow than to plant in the maximum depth of water straight away. Late April and early May are the best times for planting outdoors. Indoor aquariums may be planted a little earlier.
Fishes, water snails, etc., should be introduced a few weeks after planting, when the water clears. It is always a little muddy at first.
Cultural Routine. All deadmust be removed in the autumn. Pond weed, etc., can be raked out from time to time. Algae (green scum on the surface) is removed by drawing a sack across the surface. In small quantity these weeds do no harm, but rather good. They can also be destroyed with copper sulphate, 23 grammes per thousand gallons of water. This treatment is not recommended, as an overdose may damage fish and water plants. A less dangerous method is to stir in a saturated solution of potassium permanganate at the rate of 1 teaspoonful of chemical to each gallon of water.
It is not necessary to change the water frequently, nor to grow plants in running water. Pools and aquariums properly stocked with water plants, including oxygenating plants, fish, water snails, etc., maintain a balance of life and do not become unpleasant. Water lost by evaporation should be made good with water at the same temperature as that of the pool or aquarium.
Propagation. Most water plants can be increased by division at the ordinary planting season, exactly like herbaceous perennials. As a rule they benefit from such division at intervals of five or six years, as this prevents overcrowding.
Some kinds can also be raised fromsown in ordinary compost in well-drained pans, which should then be supported on inverted flower pots or bricks at the edge of the pool so that their rims are about half an inch below water level. is sown in the spring.
Most of the submerged oxygenating plants can be increased by. Pieces 2 in. to 4 in. long will readily in a sandy compost.
Useful Oxygenating Plants
In all these the foliage is submerged and supplies oxygen to the water. Those preceded by an asterisk are tender and must be protected in winter.
- Apium (Marshwort)
- *Cabomba (Washington Grass)
- Callitriche (Water Starwort)
- Ceratophyllum (Homwort)
- Elatine (Waterwort)
- Eleocharis (Needle Spike Rush)
- Fontinalis (Willow Moss)
- Hottonia (Water Violet)
- *Myriophyllum hippuroides
- Myriophyllum verticillatum (Water Millfoil)
- Oenanthe (Water Dropwort)
- Pilularia (Pillwort)
- Potamogeton (Pondweed)
- Ranunculus aquatilis (Water Crowfoot)
- Utricularia (Bladderwort)
- *Vallisneria (Tape Grass)