We have a small asparagus patch and freeze the stuff all the time. After blanching and chilling in ice water, I take them and lay them in a single layer on a sheet pan and run it in the freezer. When they're froze I pack them in ziplock bags-keeps them from sticking together. As mentioned, they're not as crisp as fresh but are quite good sauteed in a little garlic butter or for a soup.
Blanching is actually the reason vegetables keep in the freezer. Blanching retards the enzymes responsible for vegetables composting. Green peppers are the only vegetables that can successfully be frozen without blanching.