This whatever-it-is grows extremely quickly. It starts drooping when it's thirsty and after watering, it perks up immediately. We suspect it's some kind of tree, but have no idea. We're in North Central Texas and even though it's HOT, this plant cropped up in a planter set on concrete and is in full sun most of the day - it doesn't seem to mind. Apparently those are buds at the end and along the high parts of the shoots. Thank you!