How to Propagate Buddleja speciosissima?
Propagate by semi-ripe cuttings in summer, or by hardwood cuttings in autumn

Buddleja speciosissima · Buddleja speciosissima
Suited to southern counties and innner city microclimates only where it can be grown in well-drained soil in full sun. with shelter from cold winds, can be trained on a warm sheltered wall. Ideal for a large conservatory or greenhouse. See buddleja cultivation for more detailed advice
Propagate by semi-ripe cuttings in summer, or by hardwood cuttings in autumn