Rare in my garden are annuals, their uniform sameness unrelenting through summer. The common garden poppy (Papavar somniferum) is an annual and is welcome any time.
Growing poppies is simple and easy. Direct sow seed in the garden in a sunny place as soon as any danger of snow is past. In places without snow anytime fall through March is fine. Don't plant poppy seeds deeply or cover with soil. A light pressing to ensure contact with the ground is enough, should you care to bother with it. In nature poppies are not dependent on humans to do anything after all.
In subsequent years after the first, the poppies themselves will take care of business, reseeding around the garden in a charmingly haphazard way. You can find seed packets for Papavar somniferum at many garden stores.
Papavar somniferum (common garden poppy) comes and goes quickly in mid-spring.
In the same place where I met the elderly man and florida azalea, I grew corn one summer. There was a field next to his place I was allowed to garden. This place, outside of Roopville, Georgia, was always full of the mysterious and unexpected. Welcome to the true southern gothic, the backroads and warrens of the rural south. Unlike True Detective, our memories are real.
Anyway, I planted corn and watermelons and dutifully watched them grow. Eating corn raw out of the garden while the summer sun serves as some type of baptism is one of the great pleasures of a gardening life. That spring thousands and thousands of brilliantly red flowers appeared in and around those fields. I didn't even know what they were until the elderly fellow told me they were opium poppies.
The poppies came every year with no human help. Should you plant the Papavar somniferum in your own garden I encourage the same attitude. Let them come and go.
Poppies are used for opium manufacture. If you grow them in your garden (of which I am assured is legal) just don't scarify the seedheads. Such an act could be interpreted as changing the intent from gardening to opium production, which is highly illegal.
Perhaps the most famous and entertaining gardener to recount his experiences with growing poppies is the great writer Michael Pollen.