This hybrid is a sterile triploid (info from Jim Waddick) checked and
confirmed via other sources. I've been trying to set seed on it now for 5
years using a number of finagles, e.g,various dilutions of 2-4D dissolved
and placed on the juncture of the pedicels below the ovaries. I get more
swollen ovaries that persist for a while and seem to have rudimentary
embryos in them, but , so far, nothing. . The large groups are indeed from
multiplication of offsets, often 20-50 years old in the gardens of older
houses way up into zones 3 and 4.

Large bulbs can get to be about 5" in diameter, and they are often quite
crowded in the older plantings. Indeed, give them full sun,or as much as
you can-- and clay soil and winter wet or freezing is no problem
whatsoever.

Adam in Glenview, Z 5a