#1 Gallon
Digitalis (foxglove) is a genus of roughly 20 biennial or perennial plants in the Plantaginaceae family, most notably Digitalis purpurea, featuring tall, tubular, often spotted flowers that bloom in early summer. Known for their use in creating the heart medication digoxin, all parts of the plant are highly toxic, containing cardiac glycosides that can be fatal if ingested. 
Key Characteristics & Uses:
Medicinal Value: Historically used for dropsy (edema) and now for heart failure, the plant produces digitoxin and digoxin, which make the heart beat slower and more efficiently.
Toxicity: The plant is extremely poisonous, with symptoms including, but not limited to, a slow pulse, hallucinations (such as yellow-tinted vision), and convulsions.
Garden Use: They are popular in cottage and pollinator gardens, thriving in moist, well-drained, partly shaded, or shaded areas.
Appearance: They are typically 3–6 feet tall, with a rosette of leaves in the first year and a tall spike of flowers in the second.
Distribution: Native to Europe, North Africa, and Western Asia, but also considered an invasive, noxious weed in some US states.