The natural world is abundant in color. It doesn’t take long to discover that so many of the organisms we see every day can impart pigment across the whole spectrum. In fact, it may become challenging to go outside, just for the sheer distraction of fennel here, sourgrass there, oak galls left and right!
Harvesting plants, fungi, or lichen in the wild requires some etiquette. Foraging biological materials may be legally constrained depending upon land ownership where you venture, and some species may be rarer than others and may not be well suited to collecting. The organisms exist and thrive as part of an ecosystem, and their removal could disrupt that balance.
A good rule of thumb: take only as much as you need. Even dead material plays an important role in the food web to feed decomposers, who are in turn a food source for other organisms. Harvest where there is abundance.
For plants, it is usually leaves, stems, roots, or bark that is the source of stronger and better lasting pigments. Fruits help the plant reproduce and are a food source for birds, so if there is not a specific use for them, they are better left on the plant. (Some fruits, like elderberries, are the primary source of pigment from a plant. Proceed with discretion.) Bark should be collected from fallen branches and from the ground. Digging up a plant’s roots will generally mean killing the plant, so this is best left to plants from your personal garden or invasive species.
For lichen, collect only from fallen branches and from the ground. Lichen take a long time to grow, and are often the sign of a healthy ecosystem. But once a lichen has detached from its substrate, it can no longer live and will quickly decompose.
For fungi like mushrooms, the visible part above the surface is just the fruiting body of a much larger network of mycelium beneath the surface. Collecting these is not usually considered detrimental.
Several edible foods are also great sources of dye. Consider saving onion skins, avocado skins, or the bean water from soaking your black beans, and dying with these leftovers!
A note on invasive species: it happens that a number of “weeds” here in northern California yield dyes, and in general, aggressive harvesting of species like eucalyptus, French broom, fennel, and sour grass is considered helpful. Check with your area if this is the case for you as well.
No one list of natural dyestuffs is exhaustive. The best you can do is start gathering and experimenting on your own! It is best to start keeping a written inventory and “dye-ary” of your experiments, complete with specimens of your dyed fiber, as you explore.