Depending on how quickly it turns cold, many of the flowers from September will just carry on flowering until the first frosts. The above picture was taken in one of my borders in early October and has looked almost exactly the same for the previous 6 weeks. The calendula provides ongoing bright colour and some amounts of food but the borage, echiums, aster and sedums are all still going strong and visited by bees every day when the temperature rises to 10 degrees or more. October is also the month when common rambley ivy (hedera helix) produces is very plain looking green flowers. However, these should not be underestimated in terms of their value to the bees as they resist frosts and keep flowering and providing vital nectar right up to November. This really helps the bees top up their winter stores and can mean the difference between a colony surviving or not over the winter months.
I would not recommend planting this ivy unless you have some spare land and trees for it to scramble over; it is so vigorous that it quickly engulfs a fence and can smother small trees to death. But given the right setting and space it will thrive and not only provide bees with pollen but homes of many other insects and even birds tucked into its criss-crossed branches.