Plants I have killed

So far:

2005
huckleberry	Vaccinium ovatum	insufficient hydrogen ions
lenten rose	Helleborus x nigersmithii "Ivory Prince"	?
passion flower	Passiflora edulis "Black Knight"	Passifloraceae
2006
western redbud**	Cercis occidentalis	(bareroot never rooted)
anemone	Anemone multifida	shade?
poppy	Papaver orientalis cv.	temperature?
tuberose	Polianthes tuberosa	summer water?
2007
agave	Agave attenuata	cold
--	Deppea splendens	cold

I know, how do you kill a Hellebore? Soggy soil?

Shit, I almost forgot I murdered a clivia baby (i.e., offset) while transplanting the mom last weekend. I'm trying to get it to root though.