On 13/12/2011 17:27, AL_n wrote:

Last Spring, I planted some purple broccili there. They didn;t ptoduce any
flowering tops, but did a great job of smothering all the grass and weeds.
At the end of the season, I found they were easy to pull up and chuck onto
the compost heap, leaving teh ground much easier to work.

not really replying to your main question but:
I know you said you are not a Broccoli fan, but are you sure they were
not a variety which produce on the second year?
The ones I have at home have to spend one winter in the beds before
producing the second year...