I've found the answer to my own question. I talked to Charlene at Rosie's and she said that she recommends wheat paste bc that was what was recommended by the manufacturer of the paper.

Wheat paste is flour and water, isn't it? I would use a commercial paste product for the paper.

Well, here's the def from Wikipedia: Wheatpaste (also known as potato paste, flour paste, rice paste, Marxist glue, or simply paste) is a liquid adhesive made from vegetable starch and water. It has been used since ancient times for various arts and crafts such as book binding, decoupage, collage, and papier-m�ch�. It is also made for the purpose of adhering paper posters to walls and other surfaces (often in graffiti). Closely resembling wallpaper paste, it is often made by mixing roughly equal portions of flour and water and heating it until it thickens, or by smearing cooked rice into a paste.

Why would you use commercial paste instead?

I use a commercial paste called "cellulose paste"...pretty much what wheat paste is...but the commercial stuff mixes smoother and easier without lumps, dries clear in case you mess up.....and costs more!
Linda C

Hanging wallpaper well is hard enough without adding in a cooking project where you are hoping to get it the right consistency and hoping it doesn't dry out along the way. I imagine - but don't know - that prepared wallpaper paste contains products to resist mildew.

Also, isn't there an issue with bugs liking to eat wheat paste?

Actually, graywings, I think it's already been cooked when you buy the powder, but lumpiness is an issue and, as you say, it's difficult enough. The mildew is an issue that I'm VERY concerned about.

terriks, I hadn't even thought of that! Really good point. Someone once recommended a wheat cat litter to me and it was horrible - a mess of bugs.