Verbascum thapsus is the scientific term for the common mullein plant. The leaves of the plant have medicinal properties, and are known to alleviate cough, chest congestion and diarrhea. The verbascum thapsus plant has certain required conditions that must be met in order for it to flourish.
Verbascum thapsus is found in areas of the United States where the average precipiation is more than 3 to 6 inches per year, and the garden growing season is at least 140 days. The plant can be found in every state in the United States.
Verbascum thapsus prefers sunny conditions. Home gardeners should plant it in the sunniest part of the yard. The plant cannot tolerate shade. Avoid planting under or near trees, as the tree canopies can eventually shade the verbascum thapsus plant.
Verbascum thapsus grows best in dry, sandy soil. It can tolerate rain, but needs its soil to be very sandy to allow for quick and thorough drainage. Rich soil holds too much moisture, which leads to root rot and eventual death of the plant.
The verbascum thapsus plant is both self- and cross-pollinated. If a flower is not pollinated by the end of the day, it self-pollinates. Many types of insects visit the flowers of the verbascum thapsus, but only the short- and long-tongued bees are capable of successful pollination.
Verbascum thapsus produces a large tap root and a crown of leaves during the summer following germination. The leaves increase in size throughout the growing season, and growth ceases when low temperatures halt the growing phase. This time varies according to region, and occurs in the fall in the northern United States, and during the winter in the south. When the spring temperatures start to warm the soil, the second year verbascum thapsus will produce a 5- to 10-foot-tall flowering stalk, seeds and die.