Started popping up a a few weeks ago and at first I thought they were maybe growing from the roots of a heap of poinsettia trees I recently chopped as near these stumps is where they first started to grow.. but now that they have grown a bit and spread absolutely everywhere I'm not so sure... They are literally coming out of every bit of uncovered soil including cracks in the drive way... The stems just snap if you try to pull them out but I have dug a garden beds worth out and they are growing from massive bulbs that are the size shape and look of a large sweet potato but with a milky white flesh....
Anyone have any ideas on what they are and how I can go about controlling them
EDIT: i live an hour south of perth, about 150m from the beach.
