As the name might imply, this is a sport of H. 'Sum and Substance' which was introduced by Jan van den Top but has not been registered. It also becomes a huge mound of foliage. The leaves are moderately corrugated, have deeply lobed margins, are cupped both up and down and have a long, distinct tip. It has thick substance which  makes it resistant to slug damage.  In late July and into August, it produces large pale lavender flowers on four foot tall scapes.