Re Papaver orientale; not to my knowledge, at least here.
By mid to late summer the whole plant goes dormant.
The problem with this is that if several are planted together, in a mixed perennial bed, you'll end up with a big gap for the rest of the growing season.
(I cut the dead plant material down as quite unattractive).
Below a cultivar I planted in 2008 and which was still going strong this year.
(June 30, 2009)
