Yes finding last years stalks is a good way to find patches, also keep your eyes open for asparagus once it has gone to seed throughout summer. Then you will know where patches are for the future. I pick raspberries and other summer mushrooms and looking out for asparagus gone to seed is how I have found quite a few of the patches I pick. Something some people don't know is as long as you continue to cut spears down new ones will shoot up, all summer long. Yum can't wait to get some fresh asparagus!