How do you root a butterfly bush?

Answer 1

You can propagate them from hard or soft wood cuttings.
Hardwood cuttings are made when the plant is not growing much - usually late autumn or spring. Cut off a woody stem near the base, then cut again just under a leaf node (one of the bumps where the old leaves were). Remove the growing tip so you are left with a cutting about 12 inches long. Leave only a couple of leaves up the top and strip the rest . Plant in potting mix or sand. Water and wait until new growth is established until planting it out.
Softwood cuttings are taken in summer or autumn. Use the top new growth with about 2-4 sets of leaves. Again, trim under the lower set of leaves and remove all except the top ones, plant and water. These softwood cuttings are more susceptible to drying out, and need to be kept moist and possibly enclosed with plastic to keep the humidity up.
If this all sounds very complicated, don't worry! Many plants will root fine if cut off as described and put in the ground. The above methods, though, will increase the success rate.