By the way, your semps have already gone into some heat dormancy, so do not spray the leaves, it may just rot the inner part. But you can still water the soil directly. My semps did not close its leaves yet, so I can still freely lightly spray the leaves allowing excess water to easily drain away. And it has been so terribly windy here, so easy to dry out all the plants.
In most cases too, semps in heat stress, may just bolt, creating flowering stalks, as a final means of survival. Sadly at that point, the plant is in its final phase, so just enjoy the blooming show and hopefully you can harvest seeds...or it may then try to do little offsets to continue its growing legacy.
Summer is just a few days ahead, and already we are getting triple digit heat wave forecasts ugh....so if it is the same on your side, try to protect your plant, position it in shade.
These are my semps, positioned in the cool but still bright side of the garden. I even have it under my bromeliad, to further add some more shade.
The city trees by our fence line further helps provide dappled light when the afternoon west sun hits the plants.
they'll need some TLC to get through the summer. I'd hold off on giving them full sun this summer. If you can give them some kind of high shade or dappled sun that would be best I think. A shade cloth would be ideal until they're established. 
