I used a scrap of red that may have been Bazzill cardstock. It had a good weight to it and a bit of texture.
Beginning with the card on the right, before tapping out the pieces from the red paper after cutting them, I placed the die on the second card front and used a pencil to draw lines within the die's openings to indicate where I would be gluing the petal pieces. The cut paper pieces were slightly larger than the pencil lines so there was no worry of lines showing and needing to be erased. I used Tombow glue, sometimes applying glue to the card, sometimes applying it to the back of the red petals. I began with the smaller pieces, tapping out just a few at a time, gluing them and repeating the process. Reading this took longer than actually doing it.
I then switched and worked on the card on the left, gluing the rose cutout onto the card front with the same glue. The remaining piece of red card stock from the die cutting gave me that perfect outline for the red area of the card, it just needed to be squared off to match the white cardstock's dimensions. I used a tape runner to add this.
Back to the card on the right, I wanted a similar outlined edge but had very little of the red cardstock left. I placed the die on it, maximizing what I could salvage of the leftover cardstock and got the shape seen above. It wasn't perfect and I decided it looked better with a wider margin which mimicked the negative space created by the die itself.
Despite having a lot of stamps, I don't have many with anniversary greetings. I wanted to use this label shape, also from the Rose Garden die set, but the only greeting that fit inside was this one. It is from Stamps of Life's Anniversary 2 Celebrate set. I used a Real Red stamp pad from Stampin' Up for the words and ran the side of a red Tombow marker around the edge of the die cut label.