I agree with Lee-Roy on this one. Plants seems thirsty. It is different when these plants are in containers, compared to having them planted in ground. It can handle the heat, and it blooms nicely, but as new plants in a container they are more thirsty not yet fully established. I used to have this plant, but it did not thrive since my garden lacked full sun being shaded by trees and it hated our mild winter cold. I was a newbie in watering it then too, misunderstanding the drought tolerance aspect. I have realized later on all my plants here in summer needs a bit more water since our conditions are excessively hot and dry and my plants are in containers.
I have often wondered why my plant did not work, seeing lavenders ably growing and full of blooms in parking lots, and it became clear to me, the plants were planted in ground, in full sun, and they get their drip watering at night everyday.