Moved large, established asparagus - when can I harvest?

At my old house, I had an asparagus that self-seeded in my flower patch from my neighbor’s patch two blocks over. It did exceptionally well and is one of the best tasting asparagus I’ve ever had. When I moved, I decided to take it with me. It was huge, about 6 years (?) old, root ball at least 1.5 feet across. It took three of us to get it out of the ground and broke my friend’s shovel. In the picture, it is in one of those giant blue tubs that people use to hold drinks at parties. Last fall, we moved it to the new house.

This spring, Destroyer of Shovels (as we have affectionately named it) is showing signs of life! One large spear is just starting to come up. I know with commercially purchased roots, you need to wait a few years to harvest (I moved some of those, too), but what about this giant asparagus? Can I harvest some this year or do I need to give it some recovery time? Or should I base harvest on the spear size and stop when they reduce in size?