She just has

“I used a combination of yarns to create the delicate effect of this corsage.”

but based on the photo, the outer and centre petals are two strands of Rowan Kidsilk Haze (different colours), and the middle petal is a solid yarn similar to those used in her cardigans.

The middle petal has beads added to the knitting, as well as the beads sewn into the centre.