I see. I was thinking of a tea marketed when I lived in Kentucky.

Wasn't it originally made only from kohlrabi and hence was called "King Kohl"? I believe the rationing of kohlrabi led to the inclusion of the other "greens." That would have been during the Mahdist War, when Great Britain was critically short of kohlrabi and called upon their colonies to supply men, materiel, and kohlrabi. Canada patriotically responded with "Kohlrabi For The King" and sent so much that the nation bankrupted its kohlrabi supply for years to come -- a regular supply wasn't reestablished until the late 1950s. By then "King Kohl" tea had changed its name and formulation.

A variant, "King Coll", was marketed for a brief period. It contained only collard greens and while it was popular in some places in the Southern US it was a flop in Canada and was, like "New Coke," taken off the market.