The shameful thing happened: my 8 asparagus plants that were thriving last year failed to emerge this spring. Any thoughts? I planted them 3 years ago, they were doing well, this year: the bed is empty. They were in a bed with concord grapes, rhubarb, strawberries and very deep-planted glads that I don't bother to dig up in the fall. Everything else is up and thriving, no asparagus.