Bolting asparagus

I went away for a few days and when I got back to my plot on some of my asparagus plants the spears had bolted and the ends turned flowery. Should i pick these to encourage the plant to keep on producing?
Also when should I stop picking the spears? i thought it was mid summer's day (21st June but someone else said I should stop on June 1st.
Thanks

 

Beginning of june sounds right to me, but maybe it depends where you are in the country and how long it's been cropping for. I don't like the taste of asparagus, just grow it in the flower bed cos i like the look of it.