Marilyn, the event was added awhile back, right after the new feature was added to NGA. Here is a link
https://garden.org/apps/events...
If I have left anything out please post a comment to add information.
@JungleShadows
If a plant makes pollen Kevin has probably played around with pollinating it.
I think anyone interested in hybridizing would find this clinic very useful. Come one, come all.
Jo Ann, even spiny Euphorbia have mothers that love them.