Help needed with laurel

[avab]

Hello! I need an advice with my laurel trees. They suffered quite a bit last August when we were on vacation for two weeks and could not water them regularly during the heat season. And now with the spring in full mode they do not seem to be getting much better. There are some occasional new leaves coming out but many of the branches remain empty. Only 2 bushes out of 15 are blooming. I started watering them last week after the winter brake but it doesn't help much. I did not do it earlier since the spring in Switzerland (this is where I am) turned out rather cold and the night temperature stayed around 0 degrees Celsius well into April. I am really worried that there is something irreversible going on and would very much appreciate any advice.