My son painted the flowers in two sessions. The first time he had to be encouraged to paint the inside of the flower and during our second painting session he was really interested in painting the plates.
After they dried, I attached the flowers to the paper plates using fasteners because it was a material I had at hand. One could use glue or pipe cleaners and buttons to make the wreaths even fancier or if your crafty kid is older than mine (almost 3).
All told the project would take maybe two hours painting with 10 minutes prep time and 20 minutes to attach them to plates.
I wasn't concerned that they look too perfect because they are supposed to be from a toddler - not his mom.
Cardboard egg cartoons
Paint and supplies
Fasteners (or other attaching supplies)
Creative Egg Cartoon Crafts