This is one of those cases where there are three hostas with the same name. One is registered and, therefore, the "official" version of H. 'Tet-A-Poo' while the other is a non-registered plant and needs to be renamed to avoid further confusion.

This was introduced in 1976 by Paul Aden of New York and was registered in 2010 by Mark Zilis of T&Z or Q&Z Nursery in Illinois. It is a hybrid of H. venusta x H. 'Blue Cadet'.

This is a miniature size plant only 3 inches high by 12 inches wide. It has thick, blue-green foliage that is ovate shaped with good substance. Near white, funnel shape flowers bloom in July on scapes about 3½ inches tall.

The New Encyclopedia of Hostas (2009) states in its Miniature Hostas chapter: "Origin: ...Best in a pot until the root system is well established. Among the smallest hostas and now very rare...The blue toned leaves are most unusual for a hosta of this size."

Hosta Helper will call this plant 'Tet-A-Poo' (Aden)
 

Powell's Iris Haven nursery advertized a hosta of this name which was described as a large size mound of blue-greeen foliage with typically H. 'Sieboldiana' characteristics.

Hosta Helper will call this plant 'Tet-A-Poo' (Powell)
 

According to The Hostapedia by Mark Zilis (2009), "The plant currently being sold under this name...is not the same as the one offered by Powell's Iris Haven in 1989 & 2002 and is also different from the one described in a review of Paul Aden's introductions in the Hosta Journal... The current version differs vastly, being a small size mound of green foliage."

Hosta Helper will call this plant 'Tet-A-Poo' (Unknown)