@jmichaelp
I have an update. first sun is not a problem, it is almost 100% shade anyway, almost no plant will grow here in a sun (maybe cactus will )
Second I found a problem : the soil in this pot was too much clay. Removing plants from this soil, splitting them, cleaning bulbs end then re-potting to a new soil made from coconuts helped. One of the thing I found when removing bulbs from clay soil was almost lack of roots, and bulbs were very soft on touch. Now after several month in a new soil, new roots grew up and several strong green leaves came out.
