Re: Mary, Mary, quite contrary...
See, now I do the same (but rows instead of obelisks) I also let seven or eight shoots grow fro 3-4 years and cut them down as poles (all sorts of uses for those). Of course this way the year I had to cut them down too so altogether a real heavy job.
The only thing I plant this early up here are tatties - probably a couple of weeks into April for them - anything else tends to get zapped by frosts. I can't get peas and beans etc. out until we are into June and even then it's chancing it. Losts them all to a heave frost late in June last year.