I used the gorgeous (and free!) Daffodil Afternoon Designer Series Paper which is no longer available. If you don't have this paper, you can sub out any DSP that is mostly Crushed Curry to achieve a very similar look. The Regals Collection 6" x 6" stack has some excellent designs.
I love the filigree stamp used on the side in my daffodil card. It adds a touch of elegance and helps ground my design.
All Stampin' Up! products used in my daffodil card are listed and linked below for your shopping convenience.
Be sure to click on the video below to see 7 more daffodil card ideas. The class is no longer available, but the ideas are!