They were planted about a month ago.
Do Barberry Plants Need a Lot of Water
Certified GKH Gardening Expert
New plantings need daily water for the first 2 weeks, even twice a day if the temperatures are above 85 degrees.
Then you can cut back a bit. You need to be very vigil for new plantings this time of the year.
Adding 2 to 3 inches of hardwood mulch will help with moisture retention.