If I buy an Onion bulb at the grocery store, can I plant it in the ground and have it grow like tulips,lilies,daffodils, etc meaning are they cold hardy? I live in zone 7a. If so any specific cultivar that grows best?
Growing an Onion for its flowers
Yes, you can do that and yes, it will be cold hardy in your zone.
However, there are a lot of onion species that are grown specifically for their flowers and which may be more satisfying (that is, showier) in the longer run... or you could start with culinary onion species and eventually expand out from there.
I read after flowering onions rot and die, is this true? Do any flower year after year? Can ornamental allium hybridize with grocery store onions, what would the hybrid be like?
This message was edited Apr 23, 2014 11:46 AM
No.
Allium species are perennials that bloom year after year. By simply googling Allium image, you can see what's out there.
Possible, but interspecific hybridization occurs much less commonly than most people imagine.