The yellow part is 0.4mm craft wire, the flower stem part is 1mm or 1.2mm craft wire, I use green paper wrapped wire, I think normal wire is ok, because we will use yarn to wrap the wire.
chain 21, one sc in the second st from the hook, one half double crochet in next st, one double crochet in next 15 st one half double crochet in next st one sc in next st three sc in next st one sc in next st on the other side of the foundation chain one half double crochet in next st one double crochet in next 15 st one half double crochet in next st, one sc in next st and don't forget to put iron wire Hope it is helpful to you!