The best way to propagate and divide water lilies
Like all perennial plants, once every three to five years, lilies need to be lifted and divided in order that the soil in their immediate vicinity can be revitalised and the plants themselves can be rejuvenated.
Materials and tools: strong, big, sharp, old carving knife or garden knife; large baskets and hessian liners if appropriate; also a bag of half-inch stone chippings or pea gravel to dress the top of the baskets.
Ground sheet, large plastic bags and damp newspaper.
The cutting and the kit: A growing tip from a large lily root; a medium to large planting basket; since there are big fish in this pool, a hessian square will help; suitable aquatic loam.
SOIL/COMPOST. Either a heavy (chemical free) fibrous loam with half-pint measure of course bone meal to every 2 gallon bucketful (Francis Perry)
Or John Innes No2 mix with 2 extra Peat or Coir compost i.e. 7 parts loam, 5peat, 2 sand. This is then used without the usual dose of fertilisers added but instead bone meal in the quantities above or with 1 or 2 proprietary slow-release fertiliser capsules in each planting basket.
Dividing
1. During the growing season on a cool overcast day lift the plants.
2. IMPORTANT. Note the style of growth. Odorata and tuberosa groups grow across the soil surface; Marliacea varieties have gnarled upright growth.
The tubers should be planted in the direction in which they seem to be growing on the original plant. The rhizomatus ones that look like Iris tubers should be planted horizontally about an inch below the surface of the soil but not covering the growing point.
The radically rooted upright rootstocks should be planted upright with the root tip similarly exposed.
3. Cleanly slice off a growing tip that is about 3 times longer than it is wide. Breeders and growers will merely scoop out the 'eye' of the growing tip - there may be several of these showing themselves down the length of even a small piece of tuber. If these have got just the start of root and leaf growth, it is amazing how they take and grow on quickly into plants. Root them in a separate container in fairly shallow water.
4. Cut off the thick fleshy roots used for anchorage leaving the flexible black hairy ones.
Cut off the large fleshy anchor roots.
5. Line the planting basket with a hessian liner and part fill it with your soil. Lay the lily in the soil at a level so that is will be just below or at soil level at the angle it was when attached to the main plant. Leave enough room for a half-inch layer of stone chippings or pea gravel. Moist soil is preferable.
The lily cutting should lie in the basket at the same at which it was found attached to the mother plant.
6. Making sure the soil is firm around it. Don't forget the fertiliser. Old timers will ram the soil into place as if they were putting in the footings to a footpath rather than planting a plant. It didnt seem to do the plants any harm, but on the other hand it seems enough to consolidate the soil around the lily crown with a good drenching.
Tuck in the hessian around the edge of the basket.)
7. Spread a half-inch layer of pea gravel around the top of the basket to help hold the soil in and deter fish from foraging around the plant.
Topped up with peagravel the new lily is ready to go in a around about half its intended depth to begin with. These relatively large pebbles will help to protect it against the intrusion of Koi carp.)
8. As soon as possible get them into the water. Some people make wire handles looped through the plastic container, which they use to lower them into position. Others do likewise and lower the baskets in whilst suspending them from rope looped through the wires. I just get in there and put them in place. At least I know they are left upright then.
If you go in with waders on, make sure there is someone else about just in case you slip over.