This big poppy looks like an Oriental poppy. It is a fairly involved project, but if you take it step-by-step, you can do it. Please visit these links for a tutorial:

http://www.textilefusion.com/bookblog/?p=254 (the poppy center)

http://www.textilefusion.com/bookblog/?p=257 (making and gathering the poppy petals)

And there will be one more post after that, too.