My cure for the Summertime Blues are the Tropical Blues. I have seen loads of photos of Blue Hydrangeas from further north; while I miss the Hydrangeas, I never had tremendous luck with them because I gardened in dry shade – which is only conducive to Oakleaf Hydrangeas. I do miss those Oakleafs. Here is my best Blue Hydrangea ever. Not very impressive.
Down here in the hinterlands, I have Tropical Plumbago:
This is an interesting shrub; it arches to about 4 feet, then drops to the ground and roots so it is sort of a creeping shrub. I used these in pots as a summer annual further north and underplanted them with Blue Daze:
Blue Daze Evolvulus is a perennial here. Which still seems weird to me. I have a mass of this in my front yard that blooms nearly continuously, but only in the morning.
My final suggestion for curing the Summertime Blues, the Blue Agave:
This looks like a Tequila Agave but is not. I think you could make tequila or perhaps, Mezcal out of this plant, but it is a long and involved process and it really has to be done in Mexico. So, have a Margarita and toast the last month of Summer.