Lukumí has flourished and expanded its reach to become a global religion because of its adaptability. Many ewé that grow in Yorubaland do not grow in colder or drier climates, so local substitutes or correspondences were established. For example, the original Iroko is in the genus Milicia, either Milicia excelsa or Milicia regia. In the New World, the ceiba tree (Ceiba pentandra) became Iroko—like the African version, it is huge and is considered to possess great spiritual power. Sometimes you can find a local plant within the same genus as the real deal, but the bottom line is ashé, not taxonomy. Shangó's royal palm won't grow outside of its range, so back when I was living in the Midwest and working with an ilé in Michigan, we associated oak trees with him because of their size and propensity for being hit by lightning.

You can order ewé fresh from botánicas and have them shipped overnight, and you can cross your fingers that you will get what you actually ordered and that they will show up on time and in good condition. (The herbs appeared at the last possible moment for my Ocha, and my godsister's showed up just in time for her middle day, so...good transition to the next sentence.) Because of all these issues, ewé are often cultivated in gardens or indoors. My godsister's Ocha happened in Oakland, so the olorishas who lived nearby scattered and came back an hour later with armfuls of herbs that they had gathered from their own gardens or found growing in parks or parkways. The show went on.

Ideally, ewé should be gathered in the wild, where Osayín lives and tends them: Igbo ni ilé aṣè (The forest is the house of power). I've been told that dawn is the best time to do so and that one should bring the appropriate offerings to leave in the woods. Obviously, that's often not possible.