One of the tools associated to ninjas were the makibishi, which were meant to be used as a tool of hindering and slowing down enemy pursuit while escaping.
Based on this concept of organic tools, is there any way for a hidden group of assassins to grow medieval/modern melee weapons (swords, axes etc) like plants, or at least weapons made of mostly organic materia (that is, requiring little to no handwork other than the assembly part)? The purpose of this would be to allow for them to be hopefully less dependent of smiths and to have more easily replaceable weapons and tools. If possible, limit this to technology that existed up to the end of the Renaissance period (modern techniques to treat wood using chemicals known at the time are also valid). Magic does not exist in this world.