Every spring, my wife and I drive the back roads looking for those distinctive flowers shooting up 5 feet out of solid grass and weeds about 2 feet above water level on the inside crest of the ditch bank. The spears are huge, tender and sweet. A
gift from our ancestors to enjoy today. I must say though that this is dairy country and most of the fields are in an organic rotation of alfalfa, corn and grain with yearly top dressings of dairy manure/straw, so the water quality is not a problem.
Asparagus is growing in our new orchard, in the place where the ditch used to be, but the ditch is now a 4" PVC pipe. The orchard has been feral for a decade, but there between the grapes in a dense patch of orchard grass about 4' tall are those tiny yellow flowers above it all. So I scythed the grass and found a dozen spears shooting up. This area was completely unwatered. We installed swales and a
pond, but not in that area yet.
It seems to me that asparagus is a lot like growing service berries; they take a fair bit of patience and persistence to initially get them going but then, even if completely neglected will still produce.