Maligro's Spike not functioning correctly.

I killed the weaver, collected the spike and went to Vaal Ruins. However, upon trying to activate entrance which is covered by the choking roots, nothing happens. A message appears stating that the entrance is covered by the choking roots of an ancient tree, as if to suggest I don't have the spike whatsoever.
I have tried to repeat the quest, by dropping the spike and killing the weaver again to recollect the spike, this this did not work.
Any suggestions?