N. micrantha itself, especially the white form, is
so strongly viviparous that the vivips make vivips which make
vivips, all while attached to the parent, but it is hard to keep
going. Hybrids can be strongly or weakly viviparous, depending
on breeding, growing conditions and time of year. Certain cultivars
will only vivip in fall.
There are several ways to encourage the development of vivips
from nubs. One is to slightly wound the stem, as happens in nature
to older pads from weather events or caterpillar attack. Another
is to remove the parent pad from the plant with a few inches
of stem and float it upside down.
Once leaves have formed, baby vivips can be planted, bagged,
"bricked" or simply left to float where eventually
the developing tuber will cause the plant to sink to the bottom
and become established. Bagged in ziplocks full of water and
floated in a sunny pond, babies will actually mature somewhat
until needed. "Bricking" is a term for anchoring babies
under the edges of a heavy object to encourage the development
of floating leaves and roots.
The best method that we know of for getting viviparous plants
going has been developed by Sean Stevens -
Viviparous Tropical Waterlily
Tropical Day Blooming
'Mme. Ganna Walska'
'Mrs. Martin E. Randig'
'Mrs. Robert Sawyer'
'Queen of Siam'