Experts and BHG readers answer.
Move Spanish Dagger
Thanks for writing. This plant isn't particularly easy to move as it has a large root system, but it is possible. Dig a large hole around the base of the plant, keeping as much of the root system intact as possible. If large pieces of root break off in the ground, your plant may send up new shoots in its original spot --- so try to get as much of the root system as possible. Then plant it in its new spot, keeping it moist for two or three weeks while it gets reestablished.
---Justin, Senior Garden Editor, BHG.com