With this weeks heat wave you need to protect your trees. Putting them on the ground is the best thing that you can do. the grond will keep the roots cooler then having them on the bench.This is particularly improtant for the larch and the spruce which can die if the roots get too warm.
Next keep them watered. The hot windy weather will dry them out quickly. Also the water will cool the soil as it evaporates. This will also helpkeep the roots cooler than the air temperature.Water n the morning so that the water is available to evaporate in the heat of the day. You may need to water again in the late afternoon.
With the cool wet spring juipers were suseptable to a blight. This is a fungus that is different from the apple-cedar rust and requires a different fungucide. Check with yor local garden center for thier recomendations.