you put the dried seeds at -5 ° C for 3 months for the delayed hypogeal germination species? as for example for Lilium martagon? I have a lot of martagon seeds from my garden to do experiments.
I ordered seeds of Lilium henryi because my giant plant (2.50 m tall and 10 years old) was completely devoured by field mice last year. 
you advise me what for germination: to wait to sow in April in a greenhouse?
last year I tried this way Lilium mackliniae, but without success.
The freezing is specific to L. philadelphicum (as far as I know). After planting, the seeds germinate and produce a leaf in a few weeks (Immediate Epigeal).
L. henryi and macklinae are also both Immediate Epigeal (but don’t need the freezing step).
If you sow them now indoors, they will germinate in a few weeks, and you’ll need to give them light until it’s warm enough to put them outside (April?).
If you sow them outdoors, they’ll germinate when the weather warms up (again April).
