I grow Lemon Queen -- it's very easy and looking good at the moment. It spreads, but slowly. Also Helianthus saliciifolia (ie willow-leaved) which for most of the summer has tall very attractive plumes of foliage and finally ( Oct - Nov)produces some fairly mad-looking sprays of flowers about 9ft up. Is this the one you have? I would like to try some other varieties too -- particularly tall and very late flowering. They seem to like our clay soil.

No, it's not H. salicifolia. The leaves are completely different, long and dark green and really quite boring. They are also covered on quite coarse hairs. It has single flowers - bright yellow with a small dark brown centre. I had some in my previous garden, which looked very similar. I suspect it's a very common variety.

I inherited the sunflowers with the garden and have spent a long time trying to extract the roots from under some tarmac where they are an absolute nuisance.
The roots are about 6" long, about the width of a finger and a dark maroon colour.

I saw the 3ft high ones in someone's front garden when I was on holiday in Somerset. They had filled the whole flowerbed, so they obvious multiply quite well. They looked really good though and were standing up without support. They were just coming into flower at the beginning of August. I would love to know what they are.