Planting waterlilies is pretty simple gardening if you follow a few basic rules:
Use The Right Soil
All water lilies, lotus and marginal plants do much better when they are planted in a heavy clay soil.
Regular garden soil is the closest thing you’ll have.
Do not use an soilless soil mix such as pro-mix as they are too light and the particles such as peat and perlite will float to the surface. Mind you, so will the root of your plant. (been there, experimented with that) so all the junk will be in good company.
If you have heavy clay, you’re in luck because planting water lilies in that soil is the best thing you can do.
Use A Large Pot
Most water plants are vigorous growers and if you use too small a pot, you’ll restrict the growth. The minimum size for lilies is fifteen inches in diameter and ten inches deep (think half bushel basket). Tropical water lilies do much better when planted in twenty inch diameter pots (think full bushel baskets).
For marginal plants, I found that ten inch pots worked fine for most of them but you could tailor the size of the pot to the eventual size of the plant. Remember, don’t go too small or you’ll restrict the size of the plant.
When planting waterlilies, it is a good idea to wet the soil before you start planting. This saves the soil “lifting” and the root floating free.
Fill the container approximately two thirds full.
On hardy lilies, look for the “eyes” (buds or growing points) as these are your growing points. We want to put the rhizome horizontally or with a slight slant upwards (eye is the highest point). If you can get the eye towards the middle of the pot, it will be more aesthetically pleasing but this is not necessary.
Lay the rhizome across the centre line of the pot (this is supposed to let the roots go equally in all directions but my experience is that water lily roots will go wherever they want anyway so just get the darn root centered somehow.)
After the rhizome is situated properly in the pot, you can fill the rest of the pot.
Leave the eye at or just slightly below the surface of the soil. Do not bury it deeply – this is a water garden, not a cemetery
Plant Tropicals The Same Except
Tropical water lilies are planted exactly like the hardy ones except with more care because they’re more expensive.:-)
How Deep Should The Water Be?
There are two schools of thought on how deep to plant the lilies in the pond.
Hardy Lily Depth
Some schools of thought say to start the hardy lilies at six inches deep and then move them to eighteen inches deep when the water warms up.
The other school of thought says they are hardy plants and just plunks them down into the eighteen inch depth. I never had the time to mess about so my water lilies always went straight to the bottom.
Tropical Lily Water Depth
Tropical lilies seem to prefer twelve to eighteen inch deep water and you should never plant them before the water warms up so once it does, plunk them to their proper depth.