They need a lot of water until established. This has been an exceptionally dry summer so far. Where do you live?

They also need acidic soil (very important)....also it appears that your plants are raised in the bed,I would create a circular dam around the plants to aid in retaining the water around the root ball....Since Laurels need to be very moist when the weather is hot and dry, so as dave_in_nova said...keep them watered

If these are Prunus laurocerasus I would take issue with their requiring acidic soil. They are becoming a weed tree in woods here on most soils. You don't say where you live so it's hard to know what temps these have been subjected to. Here they will grow in quite dense dry shade such as under trees so I wouldn't expect them to enjoy heat. What cultivar are those? They seem very small. Are they a dwarf such as Otto Luyken?