Put on thick clothing and long, protective gloves. Also put on a pair of safety glasses to protect your eyes from the sharp blades of the yucca plant.
Trim yucca bloom stalks off to ground level, before seeds develop, because they spread readily by seed.
Cut the yucca blades off as close to soil level as possible. Begin trimming on the outside of the plant and work your way inward.
Dig and remove as much of the yucca's root system as you can using a sharp spade.
Prepare a glyphosate herbicide solution according to package directions, and pour it into a container.
Snip the tops of the remaining roots off and use a paint brush to apply glyphosate to the wounds immediately. Prompt application is necessary because yucca roots form a protective coating soon after injury, which inhibits the absorption of the herbicide. Apply the herbicide in springtime, while the plants are still forming new growth.
Continue to clip off any yucca shoots that develop. Re-treat with glyphosate if growth continues after the first application.