Common name: Waterlily
Nymphaea / Water lilies can be quite vigourous so it is important to choose a type that will not grow too large for the pond.
Before you choose a water lily, measure how deep your pond is and the width of the clear water where the lily pads will grow, then check with a specialist or specialist books for a variety/s suited to you pond size.
Smaller cultivars can be used in large ponds by sitting the container on bricks which effectively makes the water shallower.
Conversely do not use large cultivars in small pond or else they will take over.
As a guide, large varieties are best suited to ponds that are 900-1200mm (3'-4') deep and the smaller varieties to ponds that are 300-500mm (12"-18") deep.
Water lilies are best grown in plastic planting baskets.
Choose a container to suit the plant's vigour, line it with hessian and fill with ordinary garden soil or aquatic plant compost, planting the crown at soil level.
The most common problem in the small garden pond is they tend to outgrow their containers.
This may result in fewer flowers, excessive leaf growth or even lifting themselves above the water surface.
In their natural environment Nymphaea will spread and replace themselves, but in the confines of small garden pond they may require some assistance every few years, do this by lifting and dividing plants every three or four years.
Week 16: If conditions allow, lift containers out of the pond.
This can be quite a difficult task due to the weight of the water-logged containers, therefore it is advisable that the task is carried out by more than one person.
Once removed, remove old sections of rhizome with a knife and select young, healthy growth to replant, these are generally found at the outer edges of the rhizome.
Healthy stock is creamy-white when cut, not brown and soft, which could indicate crown rot.
Wash off any old compost, remove damaged or dead roots and generally check the rhizome for disease before re-planting.
Trim any long roots back to 100-150mm (4”-6”) in length.
Discard diseased or suspect rhizomes.
Re-Potting: line the basket with hessian or similar material, and position three or four pieces of rhizome in the basket with their growing tips facing outward, this helps to avoid competition as the crowns develop.
Fill in around the rhizomes with aquatic soil, ensuring that the roots are spread out well into the soil, and the rhizome is just covered.
If you only have short pieces of rhizome or just a few roots, anchor the plants with hoops of bent wire pushed down into the soil, this will help to prevent the pieces washing out of the container when you submerge it.
Finally, cover the container surface with gravel, particularly if you have fish in the pond, otherwise they may loosen / pull the plants out of the container.
Return the lily to the pond taking care when positioning the pot not to tip the lily out.