The yellow (occasionally white), pea-like flowers melilotus officinalis
form narrow, elongated clusters, branching off the upper ends of the long, grooved stems, which can reach heights of 8 feet or more. Each flower has a tubular, downwards-pointing corolla, supported by green bracts at the base, and which opens out when in full bloom. There may be several dozen in each cluster, covering up to 4 inches of the upper stem. The corolla is about a quarter of an inch in length, twice as long as the otherwise very similar melilotus indicus
Melilotus officinalis, like many others introduced to the US (from Europe in this case), has spread all across the country, found in disturbed ground like roadsides and fields. As its name suggests, common sweet clover gives off a pleasant aroma, and has some medicinal uses.