The hat is made of double rose petals without any foundation. The petals are pasted together part way down to make the bonnet shape. The stem is wire wrapped several times with crepe paper to make it the right thickness.
Before making the Rose Slip-Over Costume you may want to read the Basic Instructions for Making Crepe Paper Costumes and How To Make Slip-Over Costumes
This Costume and MANY others are found in the book: How to Make Crepe Paper Costumes
You can also find more Homemade Costume Ideas at our Vintage Halloween Ideas web site.