Rule Zero in my current campaign:
Druids are not restricted to the weapons selection in the Players Handbook. The only restrictions as far as weapons are concerned are that they must be made from natural materials. Bone, horn, wood and stone. Bows are also allowed. Armour is restricted to light and medium and must also be made from natural materials. Though I am willing to entertain a greater selection than offered by the Players Handbook. Wooden items that have been enchanted by the ironwood spell are allowed.
The 6th level Ironwood spell now applies to all rigid organic materials. Example: bone, teeth, shell, hooves, horn, etc.