Yaupon holly (Ilex vomitoria Ait.) is the only native American source of caffeinated tea and the small amounts of tea product that is available is currently wild-collected from diverse populations. A clonal field plantation of yaupon was grown under shading and fertilizer treatments and harvested three times in one season to observe changes in yield and phytochemistry. The June and September harvest produced more mass than the July harvest for all treatments. Shading and fertility...