If they dried out that is your problem. By the way I planted mine in a sheltered nook here in Zone 8 and it froze out. However, your hotter summer may make it hardier due to the growth being better ripened in fall.

Watering instructions based on a schedule or length of time can only be a general guideline. The plants need water when they are thirsty which really can't be determined by a schedule. The temperature, wind, humidity, rainfall, dew, type of soil, nearby trees, etc... will all affect the amount of time newly planted shrubs can last between waterings. As they grow, this interval will increase.