I planted two new roses, a Blue Girl and a Royal Highness. Living in AZ, I wasn't sure how well they would do. They were just exploding with new growth and then I think I watered too late in the day, and the Blue Girl got burned. What should I do? I was also wondering, in this climate should I still only water weekly?
Burned Rose Bush
Certified GKH Gardening Expert
Trim off the burned foliage, as it will not recover, and you do not want it to sag down onto any healthy foliage, which can cause further burn and damage. If the foliage is badly burned to about 50% of the bush or more, prune off all of the rose buds down to the first five leaf junction with the canes. This will allow the bush to concentrate its energies on generating the new foliage and not on the blooming process just now. Be sure to mulch around the bases of your rose bushes and water them every other day if it is in the mid 90's to 100's where you are. You can also test the soils around the rose bushes with a moisture meter to be sure they need the water. These articles will help with that: https://www.gardeningknowhow.com/ornamental/flowers/roses/water-roses-droughts.htm
When the sustained heat is still high even in the early evenings, keep the water low when watering the bushes and off of the foliage as much as possible. If you do get some on the foliage, just brush along it with your hand to help knock the water droplets off. If there are some cool times, those are the times to give the foliage a nice rinse down. If you can get a product called Super Thrive where you live, add some of that to a gallon of water and give that to the burned rose bush as well. I would use this treatment four times, approximately 5 days apart, and timed in with when you would do your normal watering, adding it after you have given the rose a bit of plain water.
The rosebush will no doubt be in a bit of shock but should come back with a little TLC.