This is a hybrid of H. 'Sum and Substance' x H. yingeri that was registered by Greg Johnson of Iowa in 2004. It grows into a medium size hosta about 12 inches in height with a spread of 30 inches. The leaves are nearly round in shape and have thick substance.

According to The Hostapedia by Mark Zilis (2009), "Like many other 'Sum and Substance' seedlings, 'Jaz' tends to take on the size of the "other parent"."

An article by Glenn Herold in The Hosta Journal  (2014 Vol. 45 No. 1) states that, "Johnson crossed H. yingeri with 'Sum and Substance' to get 'Old Coot' and 'Jaz'. Both have good substance and shiny leaves."