Prunus - flowering cherry trees
Some I want to look up:
guessing these three take the most cold -
Prunus sargentii sounds good
Prunus serrulata 'tai haku'
Prunus campanulata (Taiwan Flowering Cherry) - looks like it prefers warmer winters
These might work (I can't tell by the sunset zones without a lot of double checking which zones are similar to yours - have to research rest of US hardiness zones)
Prunus serrulata 'beni hoshi' (Pink Star)
Prunus serrulata 'snow goose'
Prunus x subhirtella 'autumnalis' - blooms spring and fall, double white or pinkish white flowers (don't know about the form from the description)
This is a nice one but probably too big, Prunus x Yedoensis (gets to 40' x 30)
Same with Prunus xy Akebono
Prunus - flowering plum trees (at least mine didn't have fruit..)
Prunus x blireiana - that's the one I had
Prunus cerasifera atropurpurea, nifty, but fruit (purple leaf plum)
Here's one that looks like it takes serious cold, and bears only a little fruit, good size too (but I'm looking at all of these for size and shape) :
Prunus cerasifera 'newport'
This is striking, with dark dark leaves - but sometimes sets 'a good crop of fruit' -
Prunus cerasifera 'thundercloud'
OK, that's enough for now, except that I'll look up Laurus nobilis quickly.
Anyway, looks like it gets too cold there for it (varies from 12 to 40 feet. You can find it in very formal gardens pruned into geometric shapes..)