It is unrivaled by any of the previous great advances in agriculture, and perhaps, by most advances in the biological field. For the first time, man can change the pattern of growth and development of plants, can retard growth here and speed it there. Looney said there are important differences between plant hormones and animal hormones. Whereas animal hormones are usually proteins formed in an organ or gland and transported to some other part of the body, plant hormones are not proteins, but organic acids. They are essential for natural plant growth and development.
Plant hormones have no harmful effects on the environment.
They're very safe. There is no mammalian toxicity. Why we have classified them as pesticides, I haven't the foggiest notion. As Darwin discovered, it is responsible for apical dominance, and keeps the plant growing upright. It can improve early fruit set, is used in rooting media, and is important in the formation of the plant's vascular system, which transports water and nutrients within the tree.