Identification of this branched bush with tiny blue flowers

Question

I would like to prune this bush in my garden. It wasn't me who planted it, which is why I don't know what it is and before doing any mistakes I'm asking here for help.

With this one I'm especially unsure because it has flowered right into December (down to 0-5 C) and I think the leaves only got brown when it became really cold. Now in spring there are new sprouts and flowers. It could well be that it is an evergreen when conditions aren't to rough. Right now the dimensions are 3m large, 2m wide and 1m high.

(Click on the picture for a larger image).

The whole bush from the side:

The leaves and flowers

A zoom on the flower we can see below the meter in the picture with the meter

Answer 1

It's a deciduous Ceanothus, and since it flowered into December probably an Autumn-flowering variety.

I'm more familiar with evergreen Ceanothus, which don't respond well to heavy pruning. However, some research indicates that deciduous varieties respond better to it. For example, the UK's Royal Horticultural Society says to prune in early to mid-spring and on established plants, to cut flowered stems back by about a half. It also says that thinning out the center of the bush is OK, though in your case, since the bush seems so overgrown, I would do it over the course of two or three years, giving the plant time to recover between prunings.

Answer 2

I think this is Ceanothus 'Autumnal Blue' - its evergreen, but will drop its leaves, like many other plants, in severe winter weather. If you're in the UK, the sudden descent into arctic conditions in February, following on what wasn't really a winter at all, but more an extended autumn, may have caused the leaves to drop. Pruning of this variety should be carried out in spring, as growth begins.