Posted: 08/06/2015 at 20:25
Yes, they need to be really firmly rooted or the tight buttons don't form - you get a sort of rose-like shape of loose leaves rather than the button - so yes, stake them.
As for bitterness - although modern varieties have been bred for sweetness, tradition holds that they need cold frosty weather to make them more palatable.
Purple sprouting broccoli - I've never found it to be bitter so I'm at a loss to explain that, but again they need to be firmly rooted. The soil in my veg patch is very free draining (large trees around the edge) and I find that the broccoli needs watering even in the spring to grow lovely soft shoots, so perhaps that's it?