Well, it seems to me that you are allowed to publish your poetry anywhere else; you own and always retain copyright to your Hubs and work, according to the rules. You may package and re-package your own material any way and as many times as you wish.
If you are creating a print edition book, with a few of your previously published (on HP) poems but also a lot more new content, then it is of no consequence. In the front matter of the book, however, I would put that x,y,z poem was first published on HubPages, and in what year. You may even put the link to each in that front matter.
If you are publishing it in e-book form, then you may run into the Google search engine problem, but most likely not. Generally, e-books have the same content conventions as print edition; i.e., you may want to put the front matter note referenced above.
According to Bowker, each new format in which you publish your work is a "new" work (i.e., Bowker requires you to identify each format with a different ISBN). How does this work? For print editions, e.g., you could print a hardcover, paperback, trade paperback edition. Each edition would be exactly the same content, but identified in the marketplace by a different identifier number; in the case of all published books, this identifier is the ISBN, so you would have 3 different ISBNs for the same content, different editions. When you create an e-book, Bowker would prefer each format (Amazon's .mobi, B&N/Nook's, .epub, .pdf, etc etc) to have its own separate ISBN too (as a publisher of e-books, I like to do this myself because it helps keep the marketing/sales data separate for each distributor) but there is a large debate in the publishing (and self-publishing) world about that right now.
If, however, you are publishing it in another electronic medium - blog, e.g. - then I would beware the Google "secret algorithm," as Don Bobbitt has already mentioned. And, of course, you can't re-post the same thing as a new Hub, without infringing the rules.
Hope this helps!