Yep, that ragweed. The flowers are in long green spikes at the tip of the plant, but lack any petals or vibrant color. Instead, the flower spike is made up of dozens of tiny bell-shaped pale green protrusions, with pollen on the underside of each. The leaves have a unique wavy shape and smell vaguely herbal/fragrant (in my opinion). It tends to grow as a solitary stalk or bush-like clump of stalks.