Green is everywhere in the living world and was for a long time very difficult to fix on a surface, and the mismatch is the central fact of its history as a colour.
The mineral greens were unstable or scarce. Malachite, a copper carbonate, gives a fine green but is coarse and weak when ground finely. Verdigris, made by exposing copper to vinegar fumes, is brilliant and chemically aggressive: it darkens, it attacks the paper and parchment it sits on, and manuscripts survive with holes eaten through the green passages. Terre verte, green earth, is stable and dull.
For dyers the problem was worse, because until modern chemistry there was no good direct green dye for cloth in Europe. Green fabric was produced by dyeing twice, blue then yellow, which required two dyeworks in a system where the guilds were often separated by law, so green cloth was awkward to make for reasons that were regulatory as much as chemical.
The nineteenth century solved the brightness problem and created a new one. Scheele's green, a copper arsenite described in 1775, and the emerald green that followed it, were vivid, cheap and arsenical, and they went into wallpaper, clothing and confectionery. The resulting poisonings were documented at the time and the pigments were eventually abandoned.
A colour that is hard to make and easy to make badly does not accumulate a simple symbolism, which is part of why green stands for growth, for poison, for inexperience and for the uncanny all at once.