I'm not familiar with you're climate so I can't give you a date. Instead I'll tell you how they behave in my zone 3 climate.

The poppies drop their seed in August and into the fall. The seed that isn't dropped too early will lay on the ground all winter. Temperatures can get to -30 C or -22 F or lower, but we have good snow cover which protects the seed a bit. The dropped seed sprouts in the spring.

So the answer is--- plant them close to freeze up or when it is gettimg close to the coldest time you have in your area

Ummm, I am pretty sure they have to be planted early enough to come up and form rosettes of leaves here which overwinter and bloom in early spring before our heat moves in by early to mid May. I am just not sure when that "early enough for growth, but late enough to be cool enough" date is. I definitely planted too late last year. Thanks, though, oilpainter.

Here in North Carolina, I direct-sow poppies around Thanksgiving.

I'm a big fan of California poppies (Eschscholzia californica) -- I still have some of those blooming through a summer of triple-digit heat and humidity; a few self-sowed already and there are new plants.

Foliage looks good longer than the other varieties and is actually pretty, can be cut back for more blooms unless you want to let it go to seed. Behaves better IMHO than the papaver types. Shorter stems and narrow form make it easy to grow between anything.

I grow white, pale yellow, "original" orange and purple-lavender.

Cameron

Here is a link that might be useful: purple gleam

Thanks, you two. This is great info. Hadn't thought of going by soil temp, though that makes perfect sense. I have not grown California Poppies, but have seen them. You're right, Cameron, the foliage is excellent.

Donna, it's generally suggested that you sow your poppies in the fall or even winter, where you are. You could even put out transplants at that time, but seed sowing is so easy.

This is my experience in sowing California Poppy Mission Bells seeds last year.

I scattered the seed on December 7th. I looked occasionally in the weeks thereafter but didn't see any seedlings popping up. I concluded mine was wasted effort.

We had a colder than usual winter here in Central Florida along with the rest of the U.S. so perhaps germination was a bit delayed. Anyway, in spring I began to notice sprouts of ferny bluish-green - it was the California poppies. I didn't note the date on my calendar. More and more sprouted and I ended up with a cheerful and lovely display for the spring and early summer.

In a June 1st picture I took of the garden, they are still blooming but there is some browning foliage so the older plants were on their way out. I didn't note when I pulled the final plant.

I harvested a lot of seed but I'm sure a lot more fell to the ground. I expect a big show this coming spring from that fallen seed.

June