You should repot a waterlily in Spring when actively growing.

Signs a waterlily needs repotting:

1. Leaves standing upright above the pond water last Summer

2. More leaves and fewer flowers each year

3. Smaller leaves than previously seen

How to divide and repot a waterlily:

How to divide a waterlily:

1. Lift the basket out of the pond when you see growth beginning in Spring. If you cannot lift it see Pruning a waterlily below.
2. Use hard rhizome only - discard any soft and mushy portions on pruning.
3. Cut the rhizome cleanly so that each piece has a growing tip.
4. Aim for 3-4 inches/9-11cm long with plenty of thin white feeding roots to stimulate new growth.
5. Cut back the thick, long white anchor roots to 6" from the rhizome.
6. Trim away any damaged or dead leaves on long stems but leave the young or unfurled new leaves close to the rhizome.

How to pot a waterlily:

1. Fill a large mesh basket about two-thirds full of aquatic soil or clay garden soil. Wet soil works best.
2. Make a mound in the middle of the pot with a handful of soil.
3. Push an XL feed ball into the soil.
4. Place the rhizome piece on the mound and spread the roots out over the top of the soil so they are not under the rhizome in a squashed lump.
5. You can add more than one small rhizome to a large basket with the growing tips planted at an angle & facing in different directions.
Each should have its roots spread around the basket.
6. Add soil to cover the roots and around the rhizome. Do not bury the tip of the rhizome(s).
The point of the crown should have no soil over it or it will have difficulty sprouting new leaves.

Then:

1. Water the pot gently from above. Push the soil down hard and add more if necessary and repeat the watering.
2. Put the new waterlily plant on the shallow shelf with no more than 4-6" of water over the basket top until new growth appears. You should see new growth in 7-10 days depending on the weather when you replant.
3. Lower the basket when leaves reach the surface to about half its final depth and leave it there for the rest of the season.
4. Lower again in Autumn when fully rooted through the basket

See our video below:

Overgrown waterlilies:

• Waterlilies thrive by sending root growth out through the mesh holes to surf the water for nutrients.
• Their root spread is often as large as their surface spread - this is not wrong and a successful waterlily will need this root expanse to thrive.

If you cannot lift the waterlily out of the water you can deal with excessive growth by pruning:

How to prune a waterlily in the pond:

If your waterlily is too large and has become too heavy with roots stretching out across the pond base then do not give yourself a hernia by trying to lift it out to repot it.

Instead, prune the crown of the water lily plant in the pond in the same way that you would a shrub in the garden. Use a sharp knife or pruning saw dependent on the size of the rhizome.

1. Feel where the rhizomes are going underwater:
2. The display of rhizomes (like the branches of a good shrub) should be evenly spaced around the crown. Each growing point should be heading in a different direction.
3. If the plant rhizomes are congested - cut out 1 in 3 of the close rhizomes to allow each to have its own space.
4. If they are crossing then remove the weakest and allow just one to continue.
5. When you have finished, the network of waterlily rhizomes should look like the open branches of a newly pruned shrub.
6. You can trim back the pieces of rhizome you have just removed and repot for future use as above.

See 'How to repot a waterlily' above.