This cultivar of unidentified parentage is from Mildred Seaver of Massachusetts and was registered in 2012 by her son, Charles Seaver of Delaware. A giant size plant, it grows to around 35 inches in height with a spread of about 84 inches. The blue-green foliage is moderately wavy, broadly ovate, corrugated, convexly cupped and has thick substance. Fertile, near white, tubular flowers bloom from June into July followed by viable seeds.

According to The Hostapedia by Mark Zilis (2009), "...a large-leaved cultivar with an unusual mid-leaf "hump". During the 2006 American Hosta Society auction, a single plant of 'Humbpacked Whale' sold for $3700...the spelling of the name as 'Humpbacked Whale' was confirmed by Charlie Seaver (Mildred's son)...though it appears as 'Humpback Whale' on various websites and databases."

However, in 2012, this cultivar was registered as 'Humpback Whale' so that is the official name.

The Hosta Journal, (2016 Vol. 47 No 1), in an article by Warren I. Pollock points out that, although the plant was known has 'Humpbacked Whale', it was registered in 2012 as 'Humpback Whale' so that is the official name of this hosta.