Anguished Roots in Cave of Filth

[GoD1x]

I was attempting yesterday, on my character Biam Bricklebuck(Lvl 6 CG gnome wizard), to harvest the roots of the Anguished Roots in the cave of Filth area.
I passed the heal check, the lore check and the farming check but when I clicked to harvest a tuber, nothing happened. I tried again with the same result.