Looking years ahead, planting trees on the south and west sides of your house and property will reap huge benefits when their shade cools the hot sides of garden and home.
Just be careful in your tree choices, especially those within branch's reach of the house. Choose strong trees for close in, and put the lovely, fast growing, flowering trees further away.
John, we have to be careful using those water retaining soil additives like the gel crystals in humid heat like we have here in Florida. They gather water from the air, and can keep plants too wet.