Let it grow to 6-10 inches tall. Then wire, and bend in tigher curves (Just did this myself today to cuttings). The plants should be again2 inches tall.
Plant in the graden, en let them go for 5-10 years, Every year, wire the your branches. Remove the old wires atthat time too. In 10 years you will have a trainable tree, ready for a pot & bonsai training.