Finely chop two-thirds of the yarrow, set aside the rest for the garnish, place in a bowl along with the flour, salt, mixed seeds and yeast, mix together. Pour in the buttermilk, knead into a soft, smooth dough. Cover the dough and leave to rise at room temperature for approx. 1 hr.
Divide the dough into 16 portions, shape into balls and place on a baking tray lined with baking paper. Brush the buns with a little water, garnish with the reserved yarrow.
Approx. 25 mins. in the centre of an oven preheated to 180°C. Remove from the oven, leave to cool on a rack.