Planting now during the doldrums of mid-summer is harder on you the gardener than it is on the plants. However, you must bear in mind that they are going to require more care in watering than if you waited until the weather cooled off. Letting them dry out would be disastrous but equally you must assure that you do not over-water them which would rot their roots. Use your index finger as your moisture meter. If you stick your finger (up to the first joint) into the root-ball of the plant and feel moisture, the plant does not need watering. Placing a layer of mulch over the root zone of the plants will help also by reducing the evaporation of moisture from the surface of the soil, by keeping weeds from germinating, and by keeping the temperature of the soil at a level that will allow the growth of roots.