Grow waterlilies

Waterlilies are one of the most recognisable and gorgeous aquatic plants, known for their broad, floating leaves and iconic flowers that rest serenely on – or just above – the water’s surface. Whatever your climate, they’re almost a prerequisite if you have a decorative pond, but with plenty of varieties suitable for growing in tubs, literally anyone can grow waterlilies.

Many aquatic plants have floating leaves and flowers but true waterlilies belong to five genera in the Nymphaeaceae family. There are about 90 species, and hundreds of hybrids and cultivars in almost every colour. While the three Victoria species of giant waterlilies are renowned for their supersized leaves (3m wide) and flowers (40–50cm wide), most of the home-grown lovelies are from the Nymphaea genus.

The Nymphaea genus has a cosmopolitan distribution, meaning that it’s found across most of the world. Incredibly, of the 65 species, one or more is found in almost every state, territory or country of every non-polar continent. The lovely blue waterlily (N. violacea), which is native to northern Western Australia, the Northern Territory and Queensland, is one of 15 or so Australian species. Waterlilies are highly adaptable to different climates and growing conditions. In nature, and in the home garden, they play a crucial ecosystem role by providing shelter and food for various creatures, cooling the water and absorbing excess nutrients – which helps to reduce algal problems.

Things to consider when growing waterlilies

1. Tropical or hardy? When choosing a waterlily, it’s easy to get distracted by the stunning colours, but first you have to decide if you need a tropical or hardy type. Tropical varieties suit tropical, subtropical and, occasionally, warm temperate climates. Their scented flowers grow above the water on taller stems. Their growing season is from November to June. Gardeners in cold temperate, warm temperate and arid or semi-arid climates should choose hardy (sometimes called temperate) varieties – many of which also grow well in the tropics and subtropics. Their growing season is from September to April. Most waterlilies die back through autumn and winter and start growing again in spring. Garden centres usually sell climate-compatible varieties, but it pays to check the label, and online nurseries categorise all their stock.

2. Next, pick your preferred size, choosing between small, medium and large. Small forms include miniature or pygmy varieties such as ‘Pygmaea Helvola’, ‘Indiana’ and ‘Islamorada’, a hybrid of N. micrantha and the Australian species N. nouchali. Select any of the myriad small forms for small ponds or containers. Plants grow 30–60cm wide and most need water about 30–45cm deep, but some can grow in only 15–20cm of water. Small forms can also be planted in the shallower areas of ponds.

Medium cultivars grow 60–120cm wide and need a water depth of 40–75cm. Large cultivars can grow up to 2.5m wide, so are best suited to deeper ponds and dams. They need a water depth of 75–120cm.

Most waterlily flowers open in the day and close at night, but a handful of tropical varieties are night flowering, making them perfect for entertaining areas.

3. Finally, it’s time to pick that colour! Any that are blue or purple are tropical, but otherwise there’s white and shades of pretty much every colour bar green in both tropical and hardy varieties.

How to grow waterlilies

Sun To grow waterlilies, you need a space that receives minimum of five hours of direct sunlight daily. A number of hardy types, including ‘Charles de Meurville’, ‘Wanvisa’ and ‘Comanche’, will grow and flower in part-shade.
Feeding Waterlilies are hungry and will flower more prolifically and be healthier if they are fed annually in spring. Use slow-release fertiliser tablets, developed specifically for waterlilies.
Still water Grow your plant away from fountains and other sources of turbulence.
Planting Whether you’re growing your waterlily in a pond or large tub, pop it into an aquatic basket. This prevents the plant from becoming pot-bound or spreading unchecked, lets you feed it at the growing point, and makes maintenance easier. The baskets are available in various sizes from garden centres.

Waterlilies are bought potted (usually in spring and summer) or as rhizomes. It’s also possible to buy and grow species forms from seed.

Maintenance

Waterlilies can become overcrowded and start taking over a pond or tub, reducing oxygenation of the water, which isn’t good if there are fish. They won’t flower as well if they outgrow their basket, and benefit from being divided and repotted every two-to-three years. Do this in the warmer months when plants are actively growing.

Dispose of any offcuts responsibly, as aquatic plants have high weed potential. Yellow waterlily (N. mexicana) and Cape waterlily (N. nouchali var. caerulea) are two vigorous species that are environmental weeds in parts of New South Wales and Queensland, where they outcompete native aquatic plants, restrict water flow and reduce habitat for native aquatic animals.

Waterlilies are relatively pest-free, but aphids, water snails and the larvae of a couple of water moths may attack. Never use insecticides – remove snails and grubs by hand and dunk leaves to get rid of aphids. If practical, prune off yellowing and damaged leaves, and deadhead regularly, removing the entire flower stem.

Header image by Getty Images