Yeah it should be ok. Gravel and bark chippings would be ok too. Don't forget to check that the pot needs watering as you won't be able to see the soil. if you continue to water when it doesn't need it, you could get over watering problems.

Of course, you could just use plants that don't mind being hot and dry such as Begonias or Geraniums.

I agree with Badfish, any mulch will do, but I have always used pebbles about the size of a golf ball. To check the soil underneath, in the morning lift one or two pebbles, if damp underneath don't water, if dry, water.

It helps to add water retaining crystals when you are potting plants up. I have used Oasis left over from flower arrangements in hanging baskets to help reduce the need to water too often. Either will release the water to your plants as the soil dries out. What are you growing? Underplanting shrubs with bedding begonias (semperflorens) will also help to stop the water evaporating.