Petasites often refereed to as dinosaur food, are a group of plants in the asteraceae family. Petasites are hardy perennial plants usually growing in zone 3 to 7. Plants flower early spring just as snow melts with white to pink flowers usually under 1 foot tall. By mid to late spring the foliage emerges and this group is known for producing large rhubarb like leaves. In idea conditions some leaves can be 3 to 4 feet across. Leaves grow on petioles emerging form underground rhizomes up to 6 feet on some species most average around 2 to 4 feet. Plants grow best in damp to wet conditions and spread rapidly and maybe unsuited in some situations. I prefer to plant in areas where they can spread out rather than in flower beds. I would compare them to horsetail as far as spreading habit but also a good companion plant give if you have the right area.