Water lilies are without doubt the most beautiful aquatic plants and are a must for every sunny water garden. But they need not only be used in ponds. Innovative gardeners with small gardens and sunny courtyards can enjoy them too, as they can be successfully grown in a variety of water-filled pottery containers, wooden barrels, old kitchen sinks and water features. They are simple to grow. All they need is full sun, some good soil and at least 30 cm of still water. Full sun is necessary for the plants to grow vigorously and produce flowers as well as for the flowers to open during the day. They do not like to be in a pond with a fountain or in swiftly moving water; neither do they like wind.

Nymphaea nouchali var. caerulea grows easily in any part of southern Africa, including the highveld and can be considered hardy to a winter minimum of -1 to 4 oC / 30 to 40 oF (Zone 10). In climates colder than this they will most likely be killed if left outdoors during winter. Although the blue water lily does go dormant during the winter, it should be left in the water throughout its dormancy. At the coast they keep their leaves during winter.

Two planting methods are commonly used for water lilies. Either the pond floor can be covered with about 15cm of a sand and compost mixture and the plants grown directly in this, or else they can be planted in a container which is sunk into the pond. The latter method is often preferred as the plants are more easily removed for inspection or division, or for the pond to be cleaned. Specially manufactured plastic water lily baskets are the most suitable and are available from most garden centres. As they have latticework sides, it is advisable to line them with hessian before planting to prevent soil spillage into the water.

Water lilies are heavy feeders. In a natural pond the accumulation of humus at the bottom is sufficient to maintain lush growth. In artificial ponds and particularly for container grown plants, it is important to add sufficient nutrients to the soil. If not the plant will soon use up all available nutrients and stop thriving. Just about every water lily enthusiast will have his or her preferred soil mixture. Good sieved garden loam is a recommended base although some swear by pure unwashed river sand. It can be mixed with artificial fertiliser, or two parts loam can be mixed with 1 part well rotted cow manure or equal parts loam, compost and well-rotted cow manure can be used. If using cow manure and compost it is important that it not be allowed to come into direct contact with the water. Coarse ground hoof and horn or bonemeal can also be mixed in. However, it is a delicate balance because if too much nitrogen rich material or fertiliser is used, it can cause an algae bloom in the pond which will leave your fish swimming in pea-soupy water. Also, it may encourage your water lilies to over exuberant growth. If you are too stingy with fertiliser and the potted water lilies fail to thrive, a slow release fertiliser pill can be pushed into the soil near the roots.

The crowns of the lily (the part of the plant where the leaves all originate from) should be planted firmly just protruding above the surface of the soil and the soil should be covered with a layer of river sand and pebbles in order to keep the water clean. The container should be drenched, and then placed a few centimetres below the surface of the water or to where its leaves float naturally (i.e. to the level it was in the Garden Centre). If your pond is deeper, the plant will adjust as the petioles respond quite quickly to relatively small changes in depth. Nymphaea nouchali var. caerulea requires about 30 cm, but no more than 90 cm. of water above its crown.

An easy way to get loose, uprooted full grown plants established in a natural or soil-filled pond is to tie a weight around the base of the stem and then toss it into the pond where you would like the new plant to grow. Make sure that the depth is adequate, and the leaves will find their own level and within a few weeks the roots will have grown into the mud/sand at the bottom of your pond. A new plant can also be bagged with soil in a hessian square, the four corners tied into a package which is lowered into a natural or soil-filled pond. The hessian will eventually rot by which time the plant will be established on the pond floor.

The easiest method of propagation is division. Plants may be left in place for two years, but pot-grown plants are best lifted, divided and planted in fresh soil each year for good results. The plants are best lifted and divided just before new growth commences in the spring (August). Pull or cut the fleshy roots (rhizomes) apart and replant immediately in fresh soil mixture. Each new plant should have at least one bud at the tip of the rhizome.

The blue water lily may be grown from seed, but this requires patience, for the plants take 3 to 4 years to flower. It is difficult to collect the seed, because the seed pods burst without much warning and the seeds disperse and sink quite soon. A common practice is to tie a muslin bag around the ripening pod. In this way after it bursts, the seeds cannot float away. The seed can be sown in spring and during summer (September-January). Finely sieved clean loam soil without any organic matter or fertiliser is best. Seed should be sown thinly, covered lightly with soil and then plunged into shallow water, no deeper than 2.5 cm, and placed in a sunny position. Germination should take 3-4 weeks The seedlings will look like fine grass at first, developing true leaves later. When the first two or three floating leaves appear the seedling should be pricked out and planted into individual containers and immersed back in the water. They may be submerged into deeper water and larger containers as they grow and lengthen.