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Nuphar japonicum is a Perennial
It is harvested from the wild for local use as a food and medicine
E. Asia - Japan.
Ponds, lakes and shallow streams throughout Japan[
A water plant requiring a rich soil and a sunny position. It is best if grown in still water that is up to 75cm deep but it also tolerates slow moving water[
]. Succeeds in light shade[
Root - cooked[
]. Used as a famine food, when baked it tastes like sweet chestnuts[
]. The root probably needs to be steeped in water before use in order to remove a bitter flavour[
]. No more details are given but the seed is probably rich in starch and can be ground into a powder then used as a thickener in soups etc[
Digestive, women's complaints[
]. Used before and after childbirth, it treats gynecopathy(menoxenia)[
Seed - sow as soon as it is ripe in a greenhouse in pots submerged under 25mm of water. Prick out into individual pots as soon as the first true leaf appears and grow them on in water in a greenhouse for at least two years before planting them out in late spring.
The seed is collected by wrapping the developing seed head in a muslin bag to avoid the seed being lost. Harvest it 10 days after it sinks below the soil surface or as soon as it reappears[
Division in May. Each portion must have at least one eye. Submerge in pots in shallow water until established[