In a previous question I asked how many times a ranger can attack if he has horde breaker and extra attack. Now, if he is using a bow and the Hail of Thorns spell is active, can it be activated once for each attack? The description says:
The next time you hit a creature with a ranged weapon attack before the spell ends, this spell creates a rain of thorns that sprouts from your ranged weapon or ammunition. In addition to the normal effect of the attack, the target of the attack and each creature within 5 feet of it must make a Dexterity saving throw. A creature takes 1d10 piercing damage on a failed save, or half as much damage on a successful one.
I think that this effect can be used once for each attack (so, 3 times maximum), but I am not sure about this.