Sounds like a Positioning problem.
You should have 2 ranged groups and 1 melee group. The 2 ranged groups should consist of 4 people each that are in a diamond or square formation, spread out 10 yards from each other in the formation. This is to combat the puking ability that gets put on ranged members. When spores come out they collapse to the center of the formation until they all get the inoculated debuff.
Sometimes you have 2 spores spawn in a single range group or the melee group. You need to assign a person to call out which one of the doubles goes where. We designate 1 group as Triangle and 1 as Diamond (think those are the ones DBM dosen't remove in that encounter). So if you get a double in melee, your guy says "Bob go to Triangle" ect.
Edit: You also should have your healers in the melee group so they don't have to stop healing, they just sit there the whole fight.
There is something so appealing about backhanding someone across the face with a shield.