It is hard to come up with a standard amount of water to give any plant because the soil, weather, wind and root system of the plant all determine how much water a plant needs. I suggest you poke your finger into the soil and see if there is moisture one knuckle deep. Do not water if the top one inch of soil is still damp.  It is most likely your new plant is suffering from transplant shock at being transplanted during the warm summer months instead of lack of water. Give the new plant a few more weeks and then look for signs of new growth. Once the roots become established your plant should fill out again. Keep growing, Marianne Binetti