Sunflowers are not an obvious plant for bees and there is very little written about them in this context but they appear to be quite beneficial. Sunflowers are a really popular plant for any family with small children because they are so easy to grow from seed and so dramatic. But I think adults really enjoy them too which explains the proliferation of different types sold in recent years. In most garden centres you will find at least 4 different varieties: giant ones, red ones, multicoloured etc.
The bees dont really care what colour they are and so far I am not finding any seed varieties that are likely to be sterile (and therefore deficient in nectar or pollen).
I grew a big clump of them at the entrance to Rosybee this year just because I wanted a big splash of colour and some height at the back of our newly planted entrace bed. I planted them out very late - around the end of June - and they didnt really get into full flower before mid August but I notice there are still a few flowers now in early November as the frost has not got them yet.
I have observed bees on them every sunny day since they flowered so they have made it onto my recommended list.