Posted: 11/05/2016 at 14:08
I had one, that I planted, for about 16 years. I didn't harvest the first year, I harvested very lightly the second year. In France, where I live, the crowns are already 2 years old, I have seen 1 year old ones in England so expect that would make a difference. Mine were green asparagus so I didn't earth them up. In France they grow more white asparagus and that has to be earthed up.
You must keep it weeded, by hand is best so that you don't damage the roots. Then you leave them to grow until autumn when you cut them down. Then you can mulch them. They like fertiliser in early spring.
Unfortunately, I got bindweed in mine which was impossible to dig out without damaging the asparagus, so eventually I dug it up. But it gave us loads of spears over the years.