I've been waiting for the Small Leaved Lime Tree, Tilia Cordata, to flower. The time is near.
Not to be confused with the citrus trees which bear Lime fruits, this attractive tree is a big producer of nectar and it's common around Oxford. There are several large mature trees on Parks Road and South Parks road. There are many more around the city and in Headington
The flowers are said to give a very tasty honey and they produce lots of it. I think that I had some from a frame which I took from one of the (then) new colonies in the city. It was fantastic.
I can look out from a 2nd floor window into a Lime tree in Headington. I'm fairly sure that there are flowers showing. They attract the bees for a few days before they yield nectar. I'm told that it drives the bees a bit mad. The weather has turned wet so I rather hope that the trees are not flowering.
It may be time to check my spare supers.
Update 11/06/2017: The Lime trees in central Oxford are definitely flowering lower down. Their tops are not in flower yet. The trees in Headington flowered early, which fits my view of the different micro-climates. Central Oxford is colder because of the rivers. Headington is more windy but is warmer. I definitely notice this difference cycling down Headington Hill in the morning.