you will probably get more spears appearing this year, cut NONE of them. mulch the bed overwinter with good homemade compost, or well rotted manure. next year you can (if you wish) cut ONE spear per crown. again mulch overwinter (after cutting down dead fern in Nov/Dec). then the followiny year cut as much as you can up until mid-summers day. Patience is a Virtue, so they say! ;D ;)