Rub support up the wrong way over Henry's nonsense (7)

I believe the answer is:

rhubarb

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'nonsense' is the definition.
(nonsense (slang))

I cannot understand how the remainder of the clue works.

(Other definitions for rhubarb that I've seen before include "Reddish leafstalks cooked and eaten as fruit" , "Stalky fruit" , "In America, heated dispute" , "Leaf stalks eaten stewed" , "The stems are edible when cooked, the leaves are poisonous" .)

I've seen this clue in The Independent.

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