Honey fungus...

We have been digging out a large tree stump this weekend. It was the stump of a corkscrew willow that died around 6 or 7 years ago.  We build our decking around tree 10 years ago and then few years later it died.  We had it cut down and taken away but we couldn't grind the stump out at it was within the deck!  I remember my husband drilling holes and pouring some sort stump rotter into it and then we build a meter Sq planter around it and filled it with soil and have grown prerenials successfully within it each year. We naively thought that when we dismantled the planter the stump would have rotted!  No - it was there and we worked all day long trying to get it out. Admittedly we have got it down to at least 18 inches so we can now potentially plant a bed there? (Patio slabs are being laid in the middle.  Im pretty sure we have honey fungus across the other side of the garden where a sorbus died over a couple of years and the fungi that sprouted all around that root looked exactly like the pics online.  Do I need to try and get anymore of this willow stump out - as I'm typing this I think i already know the answer is yes!  Sorry for waffling on   What plants should I avoid planting there please?