February 2023
- Water lily not producing flowers. Why?
Water lily is the common name given to flowering plants in the botanical family Nymphaeaceae. Not to be confused with lotus flowers (Nelumbo), another aquatic plant species. Water lilies are flowering pond plants that grow from tubers planted in the soil in a body of water. They produce thick green leaves called lily pads that float on the surface of the water and are popular, aquatic plants of various sizes, for growing in ponds and lakes. They range from large, vigorous cultivars that spread several metres wide, to dwarf forms for small ponds or even a half-barrel. They are one of the most popular and instantly recognisable pond plants. The many-petalled flowers come in a choice of colours, including white, pink, red and yellow. They are beneficial as well as decorative, as they provide shelter for pondlife and the shade they cast helps to deter algae.
These hardy, outdoor perennial plants live for many years, dying down in the fall and re-sprouting in the spring. There are also tropical waterlilies which tend to have larger, brightly coloured flowers but these need warm water of at least 70F or 21C in the summer.
It is important to select the right type of water lily for the size and depth of your pond. Many water lilies are vigorous and can spread to cover several square metres, although there are options for all pond sizes. Dwarf/small cultivars reach 30–60cm (1–2ft) wide and need water 30–45cm (12–18in) deep. Medium cultivars reach 60–120cm (2–4ft) wide and need water 45–75cm (18–30in) deep. Large cultivars reach up to 2.4m (8ft) wide, and need water 75–120cm (30in–4ft) deep.
Some popular cultivars are: White water lily: Also called the American white-water lily, white water lilies produce a showy display of white flowers that bloom during the day. When planted in full sun, the lily pads can reach up to 12 inches across; 2. Pink water lily: One of the most common water lily plants, these lilies have bright yellow stamens and soft pink flowers; 3. ‘Helvola’ water lily: Helvola water lilies are hardy and ideal for small ponds since they only spread about three feet. They produce small, bright yellow flowers; 4. ‘Arc en Ciel’ water lily: These winter-hardy water lilies have light pink, star-shaped flowers and pads bespeckled with maroon, pink, and white blotches; 5. ‘Pygmaea Rubra’ water lily: This hardy water lily has round leaves and cup-shaped flowers packed around delicate stamens. They come in an impressive range of showy reds and pinks.
Maintaining the health and flowering habit of the plant starts with the location and habitat. They need calm water away from pumps and fountains or any other form of turbulence. Water lilies need to be planted in an aquatic basket with mesh sides lined with hessian, unless the lattice is very fine. Use a good quality, aquatic compost or a heavy, clay-based loam. Trim back any really long or damaged roots and any dead leaves. Plant so that the crown is at the surface of the compost and firm it in well. Add a layer of pea shingle or fine gravel to keep the compost in place and lower the basket carefully into the pond so the crown is covered with 15–25cm (6–10in) of water, and the young leaves float on the surface. You may need to stand it on bricks initially. Lower the basket in stages as the plant grows until it is at the recommended depth. Water lilies should be planted from late spring to late summer. Make sure to follow the planting depth for the variety that is chosen, as planting too deep or too shallow can inhibit flowering. To promote healthy flowering, plant the lily where it will receive full sun for 6-8 hours each day. There are a few varietals that will tolerate a little shade, but they still need at least 4 hours of sunshine each day. If you’re putting your lily into a container instead of a pond, choose a decorative container specifically designed for container water gardening. That way, there’s no hole to fill in the bottom of the decorative container and you don’t have to seal the insides to eliminate seepage. Choose a container at least 12 to 15” deep with a diameter of 24 to 36”. Fill the decorative container with water before placing the water lily in its aquatic planter into the container. Carefully place the fabric planter with your water lily into the pond or decorative container, slowly lowering it at an angle while the bubbles escape. Tilting the water lily in its aquatic planter while lowering it into the water-filled decorative container will avoid turbulence.
Water lilies are vigorous feeders and need a slow-release aquatic feed each spring. This mostly comes in tablet form that is pushed down into the compost so that it feeds the plant, not the water. Remove dead flowers and leaves where possible to prevent them decaying in the water. Hardy lilies do not need any protection over the winter as they will go into dormancy and start regrowth once the water starts to warm in the spring. Tropical water lilies need a water temperature of at least 10C or 50F over the winter. They can be removed from their baskets and the tubers stored in damp sand at 10C or 50F until water temperature can be maintained at the requisite temperatures. Most water lilies should be divided every four to five years, to prevent them becoming overgrown and congested. If leaves are pushed up out of the water, rather than floating on the surface, the plant needs dividing. Congested is the term used to describe a dense mass of overcrowded roots in the ground or a container.
Reasons for poor flowering or lack of flowering include: 1) Lack of sunlight. Water lilies need full sun for six hours or more per day. If your plants are in the shade or partial shade, can they be moved into a sunnier spot in the pond? If not, can a small pond be dug in a more suitable location in the garden to accommodate the lilies?; 2) Are the lilies being fertilised regularly with an appropriate, tablet form fertiliser? A lack of nutrients will cause poor flowering or a lack of flowers altogether as well as prematurely yellowing leaves.; 3) Water lily pests such as water lily aphid, water lily beetle, brown China mark moth, chironomid midge (scientific names Rhopalosiphum nymphaeae, Galerucella nymphae, Elophila nymphaeata, Chironomidae) and pond snails are most active in the summer. The main symptoms are leaves being eaten resulting in a ragged appearance. Some of these pests will also damage flower buds. In small ponds where plants can be reached safely, visible pests can be wiped off the leaves or washed off with a spray of water but many of them are just part of having a pond and may have to be tolerated in small numbers. None of the insecticides available to home gardeners can be used in a pond or water feature, because of the danger to fish, amphibians and all other forms of aquatic life.
Sources:
https://www.hgtv.com/outdoors/flowers-and-plants/flowers/growing-water-lilies
https://blog.lilieswatergardens.co.uk/2019/07/21/why-wont-my-water-lily-produce-flowers/
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