I think Dr. Christiane Northrup explains it best on her radio show, Flourish.
Flower essences are infusions made from the flowering part of a plant. The process of sun or moon steeping captures the energy imprint of the flower. So, unlike essential oils or herbal remedies, which contain physical substances extracted from plants, there is no physical part of the flower in a flower essence, only its healing vibration. And, every flower has a different healing quality.
Flower essences offer a wonderful way to heal and grow because they act as catalysts for change at a deep emotional level. The positive changes that can occur from using flower essences include feeling more confident and creative, experiencing more joy, being more forgiving, forging better relationships, having more clarity and focus, and even cultivating a deeper connection to your Higher Self.
When you use a flower essence you are connecting on a spiritual level with nature and your guides. So don’t be surprised if you start to gain clarity about your life’s purpose while using flower essences.