Meaning of Early Modern English "iuie"

Iuie stands for ivy. Last time, 'v' was also written as "u".

Just as an addition, to make the meaning of that sentence clear.

"Saleable wine needs no iuie bush which prouerb importeth thus much."

This is referring to the expression "Good wine needs no bush." The origin of this expression was the Greeks, who hung an ivy bush outside their shop as a sign that they are selling wine. The expression is implying that if the wine is really good stuff, the seller doesn't even need to let the people know that he is selling wine.

Hence, the usage of "iuie" in this sentence.

You're right - it's ivy. From The Works of William Shakespeare, Volume 4 I find this:

In Mr Gomme's delightful antiquarian collection, The Gentleman's Magazine Library (Dialect, Proverbs, Word-Lore Section), I find the following curious contribution - "The Bush, the principal tavern at Bristol, and the Ivy Bush, the head inn at Carmarthen, originated in the ancient practice of hanging a bush at the door of those houses that sold wine, whence the proverb 'good wine, etc.'"
...
Again, in that very curious volume Earle's Micro-cosmographie (1628) we have amongst the "Characters" a description of the "Tauerne", in which the writer remarks: "If the Vintners nose be at the doore, it is a signe sufficient, but the absence of this is supplyed by the Iuie bush" (Arber's Reprint, p 33).

In Abraham Fleming’s The Diamond of Deuotion, Cut and squared into sixe seuerall points, A Documentary Edition is reported the following sentence:

Is it possible that the lambe and the woolfe, the spider and the flie, the falcon and the feasant, the hound and the hare, the peacocke and the snake, the cat and the mouse, the owle and the nightingale, the iuie and the oke,¹⁷⁶ the vinetrée and the colewort, ¹⁷⁷ or what else is of contrarie inclination, should agrée together, & the one not spoile the other?

At the end of the page there are the following notes:

¹⁷⁶the iuie and the oke: the ivy and the oak.
¹⁷⁷ Cf. Rabelais, "for it is more their opponent and enemy...than cabbage to vines" (Gargantua and Pantagruel 370).