by Kirk Strawn, PhD
Image provided by Charlene Strawn
Dr. Strawn demonstrating how to hybridize a waterlily in 1998
In the hot weather of summer, many of the otherwise fertile hardy water lilies are sterile. In College Station, Texas, I pollinate hardy water lilies mid-September through mid-October, but pollination in the spring would also be good if it weren't for all of my time, which was going to digging and shipping.
To hybridize, find first day flowers. They have a pool of liquid covering the stigma. This is a large area in the center of the flower. Put the pollen from a second day flower into the pool of liquid and stir it around. It would be good to do this as soon as possible to beat bees and other insect pollinators. However, the second day flower may not release its pollen until later in the morning. You can use pollen from third day flowers. However, the bees may have removed all the pollen from anthers of the third day flowers. They can also remove the pollen from second day flowers before the morning is over. To keep insects from removing the pollen, you may have to cover second day flowers with netting before they open in the morning. The liquid covering the stigma may dry up before the flower closes. Rub pollen on the dry stigma and you may still get fertilization. I tend to remove one anther full of ripe pollen from a second day flower and stir it around in the fluid covering the sigma of the first day flower.
Covering a flower before it opens the first day with either netting or a plastic bag to prevent pollination is probably the best procedure. However, I have gotten very good results when insects have not been excluded prior to my putting pollen on the stigma of the first day flower. After putting pollen into the pool of liquid covering the stigma, I cover the flower with a plastic bag. Use the tie that comes with the bag to smugly attach the open end of the bag to the stem below the flower. When the seeds are released, the stem will keep them from being lost from the bag. Even if you are slow to collect the seeds and the stem rots, many of the seeds will remain in the bag.
The seeds have a covering that makes them float the first day after they are released from the seed pod. They could float longer if the weather is cool. I leave them in the bag until the covering rots off and the seeds sink. I tie one end of the plastic ribbon to the bag and the other end to a stake. This keeps the bag from getting lost on the bottom of the pond. The colored plastic ribbon helps one locate the seed.*
The washed seeds can be stored wet in the plastic bags. Keeping them in the refrigerator prevents sprouting in the bag. Tropical seeds can be stored dry, but hardy seeds need to be stored wet.
I plant the seeds in pans of soil out doors in light shade. I have planted seeds under artificial light indoors, but the little plants have died when exposed to sunlight outdoors. I scatter the seeds on soil an inch or two thick. I cover the seeds with a thin layer of sand after scattering the seed on the soil. I put an inch or two of water over the sand. Laying a piece of newspaper over the soil before slowly adding water keeps the seeds from being washed out of the soil. When the seedlings have two or three surface leaves, they can be transplanted into pots. I use gallon pots. In my hot climate, they may bloom by the summer following sprouting but in cold climates it takes longer. Most seeds of hardies planted in the summer and over wintered outside in my part of Texas sprout in the spring but some sprout the summer planted. Some hardy may not sprout before the second year or later.
Marliac had a policy of not releasing fertile water lilies and his descendants continued this policy. I believe that a few of Marliac's hardies have some fertile pollen. The plant sold as Arc En Ciel is fertile. Most hardies by other hybridizers are fertile. Most tropicals are fertile. My best success getting excellent new hardy varieties have been using Texas Nympheaa Mexicana pollen on fertile hybrid hardies. I have not tried the reverse cross.
For propagation from hardy tubers, cutting off the main plant from the rest of the tuber will cause the eyes behind the cut to develop into plants. The eyes may die otherwise. You have a head start on growth of new plants if you leave the posterior parts of the tuber rooted in the soil. You can get worthwhile survival of eye pieces even if the tuber is dug up before the eye pieces are planted. Transplanting the main plant gives more reason for the new plants to develop. Any eyes cut off with the main plant can be potted individually in shallow water in gallon pots. Include a cross section of the tuber with each eye to give it nourishment and help survival.
* Bob Strawn added in 2005: "Dad started putting a small chunk of Styrofoam in the hybrid bags to further insure that they could be found."
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