Laburnum x watererei 'Vossii'
I don't usually see one of these trees around these parts, even more rare to see 4 planted as street trees in a garden here in the Berkeley hills. It seems strange to me that this tree has such a disparate climate adaptability, Sunset says zones 1-10 and 14-17, which means it isn't good anywhere down south. I remember seeing classic English and European garden photos with pergolas or allees planted with these, but it is quite rare to see this tree here in the SF Bay Area. I suspect it is somewhat short-lived here, anyone growing this long term to be able to say? Simply gorgeous in bloom at the moment, remind me a bit of the tropical Cassia fistula in bloom.
Here is a link that might be useful: Laburnum x watererei 'Vossii' in bloom