It's actually wrong, the part of Germany you talk about is geographically called "Middle Germany", since Eastern Germany was :" Pommern,Schlesien,Westpreußen and Ostpreußen". Pommern and Schlesien in fact never belonged to Poland[since the early middle ages until 1945 they were never part of Poland] and were unrightfully (against the German proto-Constitution called "Grundgesetz") "given" to Poland. They will most likely have to be returned to Germany according to the peace-treaty after the 2nd worldwar once a righteous political party gets elected, but that's another thing to discuss elsewhere.
Es wimmelt Blindgänger is still wrong German [trust me, I'm German and it's my mothertongue], the correct alternative would be :"Es wimmelt von Blindgängern/Es wimmelt vor Blindgängern". The denotation of the German word "wimmeln" is "something is moving alternatingly in different directions very fast" [like bunches of roaches or maggots]. However, you need to add a preposition, since the word order of "Es wimmelt Blindgänger" is gramatically wrong. [To build a sentence from this that makes actually sense, you'd have to add an article in front of the word "Blindgänger", e.g. "der Blindgänger" , which would result in the constellation : "Es wimmelt der Blindgänger", which is, as stated before, wrong word order (Verb followed by Subject instead of the other way around) and only used in poetry and songs].
So,to stay true to the actual meaning of the sentence, you have to use either preposition "vor" or preposition "von" in front of the object "Blindgänger". You can decide wether you want to put the stress on the subject "Es" (which is the location where the action takes place; somewhat bizarre if you consider that it's the subject and not an object of the sentence) by using "vor" (this means it's important to note that it "wimmelt"{ x teems with y} and where it "wimmelt") or you want to stress the object by using "von", (which gives a clear directional movement away from the object in the direction of the subject, meaning that it's actually the object that's causing the action indicated by the verb and not the subject, thus making the object the pseudo-subject of the sentence and vice versa).
The last thing to do is to change the word form of the object from its nominative plural form "(die)Blindgänger" to its dative form "(den) Blindgängern" to patch up the grammar errors.