Lee-Roy from what I have read and my own work, I have found that anything that makes a bulb is VERRRRRY slow to grow. Very.
I have not grown Hymenocallis. I have Siberian Iris, Dierama and Dietes. The latter was extremenly slow to germinate. I had basically given up after months. Then they popped. Dittos for the Siberian Iris. The Dierama was a bit faster.
And in both cases, once they started it was slow going. Months and months to get to 2 -3 ". Notes said 10 months for 3 ".
Anything that makes a "bulb" (broadly defined) is putting most of its energy into making the bulb. Not the leaves. But it needs the leaves to feed the bulb.
It was close to a year before the Dietes got to 12 ". Measuring today, nearly 2 years from seeding, they are 28".
In my area, the Siberian Iris is hardy - the other two not. At about 8 months, I planted the Siberian Iris in my garden and they have done well. They got to about 18 + inches this past Summer.
The Dierama and Dietes are in 10 " containers and I winter them over indoors in an unused bedroom near windows. It stays quite cool in there and both seem to go into dormancy. I water them just enough to moisten the soil, but no more. Do not want to risk rot of the bulbs.
I hope the Siberian Iris to bloom maybe in '16 - '17 fer sure based on research. I likely will not see Dierama or Dietes blooms til '17. Note that these two are placed out in full sun outdoors early May and are brought in during October. I water them daily or every second day at most. It does take dedication to grow bulbous plants from seed. ;-)
I hope that this info may be of some usefullness and best of luck with your Hymenocallis.
is one of the better sites for anything bulb related.