When creating spells for a specific purpose you may want to use herbs or flowers that resonate to a specific elemental power, for example - when igniting the "flames" of passion - you might want to saturate the space with "fire" herbs, when doing a moon spell you might want to use water herbs. Alternatively, for balance you might want a little of each. With that in mind, here is a comprehensive listing of the four elements and their respective herbal correspondences. There are many different lists of elemental herbs - this was the most extensive one I found. Not every one agrees as to the elemental properties of some of the herbs listed. When in doubt, go with what seems right to you.
Earth: Alfalfa, Barley, Beet, Buckwheat, Corn, Cotton, Cypress, Fern, Honesty, Honeysuckle, Horehound, Horsetail, Knotweed...
I am so sorry to do this to you, but this post has been moved to my new website, Magickal Apothecary, hosted at shirleytwofeathers.com, and can be found in its entirety here: Elemental Herbs
As you explore this site, you may find links to a "page not found" instead of something cool and magickal. For this I apologize. I am very working hard behind the scenes to restore those pages along with a link to their homes on my new website where they can be viewed in full.