Just cut the old flowering stems only back. But the seed pots are still attractive so you could just leave them. Collect the seeds if you like. Then just let the foliage die down in the autumn. The one that you lost last year might just be that the roots got too wet and rotted off during the winter. Future plantings might help if you incorporate some sharp sand or grit mixed in the soil.

Thanks I may just leave the seed pods and tidy it up later .I’m still hoping my patty’s plum will show up next year .

Apparently Patty's Plum prefers light shade. Regular watering during germination is probably the key thing.
https://www.telegraph.co.uk/gardening/how-to-grow/how-to-grow-poppies/

are all your poppies of the same group as Patty's plum ie Papaver orientalis? the reason I ask is there are many that are annuals and will die this year. if they are Papaver somnifera the 'opium' poppy then dead head and if you want seed just leave one head on to dry as poppies produce large numbers of seed.

If Patty's plum has not put any leaf/growth on at all then I suspect it has died.

I’m not sure I don’t have label.How can you tell what kind it is? I’m going to dig up patty’s plum and put it somewhere else and see if it will revive.
Thanks for all the other replies.

leaves of the oriental types are hairy. opium type are hairless and look more 'eau de nile' or as my girls say a chalky green colour, also smooth.
if you can add photos to your question of the poppy you want info on we can do our best for you :o)

I planted Patty's Plum a few years ago and after the first season I never saw it again so I think it might be a little more temperamental than the usual Papavers.

Ihave just moved patty’s plum .it was dwarfed by another plant .it doesn’t look dead .The red poppy hasn’t hairy leaves so must be an opium one.thanks for that info I’ve always wondered.