Certified GKH Gardening Expert
I would not recommend burning the plants. If you wait until the soil is saturated and use a good shovel for the job, you may find it easier than you think to pop the large fleshy roots out of the ground. If that sounds like too much work, you can treat the plants with an herbicide. Glyphosate will do the job. Keep an eye on the treated plants, and spray them again if they re-sprout.