Take 3 inch long stem tip cuttings when there is enough new growth to do this, probably about June-time. Trim off just below a leaf joint, dip in hormone rooting powder and put around the edge of a small pot. Water in and put in a propagater or clear plastic bag. Put ina bright but shaded place and they should root in afew weeks. Pot on individually and look after them til next spring at least. Pot on as necessary. Ordinary potting compost is fine.

I agree with Volunteers general method but i usually take them a bit later ,usually mid to late Julyand put them straight into a shaded unheated coldframe . I overwinter them in an unheated coldframe and pot them on about mid to late April. I get a 95% success rate using doing this.

Do both! Just to be sure!!