I think you could use almost any yarn for these flowers. Inspired by clematis growing in a friend’s garden, I chose a deep blue pure wool felting yarn (from Knitshop) for one version and a pale pink bamboo blend (Anchor Bamboolo) for the other. For the centre, you could use an eyelash yarn or do what I did with the pink version and separate the threads of the bamboo yarn, which produces the desired effect.