I have a shrub rose ("Wandering Minstrel") that I planted last year as a bare root. It didn't do much then but this year is starting to put on a good spurt of growth. Most of this, however, seems to be concentrated on one long stem coming up from the base, which is already very flimsy-looking. There are a couple more stems starting to grow but none as vigorous as this main one. Should I: (a) Put a support in for this long stem and let it keep growing? (b) Cut it back and encourage more growth from the base? I've tried to take some pictures to show the problem, not sure how effective they are though!