You can make some wonderful poppies out of felt.
I used to wet felt the different colours separately (petals/leaves/stalk, etc), cut out shapes, then stitch and needlefelt everything together....which looked lovely...but, for a small brooch, was a wee bit complicated and time consuming.
I wet felted this poppy using a new technique (do keep watching Youtube/ googling techniques for ideas and inspiration!) Using two small squares of bubble wrap (one with a 2p size hole in the middle) I was able to wet felt the entire poppy all in on go . The "hole-y" bubble wrap separates the petal layers from the stem which I fed through the hole and rolled between my hands to felt. The felting needle, my faithful friend, was used to fine tune the smaller details. Pulling and shaping those petals whilst the wool is damp creates even more of a 3D effect. Add those brooch pins and hey presto!!