Medicine in Plants for the Earth and for Us
We use plants as a source of food and medicine, to revel in its beauty, to use as fuel, forage, fodder and fiber, and we select for genes, whether intentional or not, that help us meet our wants and needs. We often do not consider that plants have their own goals, and that they work together with soil life, other plants, and other organisms to create a fine-tuned, mutually beneficial, holistic ecosystem. We must be intentional to support this fine-tuned system, because the efficacy and abundance of plant medicine is dependent on the resilience of the inter-connected natural world.
Plants are supported and communicate with each other through the underground network of special fungi called mycorrhizal fungi. The mycelium of these fungi have a symbiotic relationship with plants, trading mushroom immunity for plant foods. Mushrooms offer immune benefits to people as well, and we see again and again that what is good for people is good for the Earth too.
Plants also communicate through chemical messages via volatile oils that circulate in the air. We use volatile oils in herbal medicine for their carminative and antiseptic effects, to calm our stomach or heal our lungs, and plants use these essential oils too. Phytoncides, produced in abundance in forest ecosystems, are a type of volatile oil that are used by plants to communicate threat or infection to their allies and neighbours. The phytoncides produced in the forest also have a beneficial affect on us, as we walk through the woods and breathe them in, our white blood cells increase, our blood pressure decreases, and our cortisol levels are reduced, and all of this supports and enhances immune function. 
Plants also produce many other constituents such as flavonoids for colour to attract pollinating insects and sugars, or nectars, that are used by pollinators and are also traded with the mycelial network below for immunity and protection. Many plants produce specialized chemical compounds such as alleochemicals and phytoalexins to reduce competition or deter predators.  When plants are threatened, near-by plants start creating these compounds to help protect themselves. The network of mycelium, intertwined with plant roots, help move plant compounds to eliminate the threat or transmit messages to other plants. 
The antimicrobial, bitter, mucilaginous, and antioxidant benefits we seek from plants, are the constituents that plants have made for their own benefit and for the benefit of many other plants and animals. Each time we take medicine for ourselves, we should remember we take medicine from the Earth. We can give back by contributing to nature’s resilience, whether we own land or not. The backyard garden or tree we plant, or the flowering potted herb we grow on our deck, gives back to what we have taken from, and we create something useful for future generations to benefit from as well.
I’m Estelle, a long-time herbal medicine student and nature lover! I have been learning about plants for many years and I’m so happy the journey never ends. When I first learned about Permaculture and began dreaming of my homestead and farm, the love for plants and their medicine grew from there! I I spend my time studying herbal medicine and running my small business; Understory Farm & Design.
1 https://www.ncbi.nlm.nih.gov/pubmed/20074458 Effect of phytoncide from trees on human natural killer cell function
2 Herbal Constituents, Lisa Ganora