Q.new weeping cherry
I planted my weeping cherry about 5 weeks ago in mid June. About a week later our area had a heatwave with temps in the 108 to 112 range. I left my husband in charge of watering it and told him to deep water twice. He put 2 drip lines around it and deep watered once. In the last week I have noticed the leaves are curling in on themselves. They are still green, but I don’t know if I am watering too much or under watering it. I used a water meter today all around the tree and it indicates it is moist. Any suggestions?

Water the weeping cherry a few times each week for the first few months after planting. Keep the soil moist to a depth of 1 to 1 1/2 feet. Check the depth of the moisture about an hour after watering. You can use a water moisture probe.
Water the tree once or twice each week after the first few weeks. It can tolerate dry soils after it has been planted for a few years but, for the first two to three years, the soil should not be allowed to dry out completely. Letting the soil dry will drought-stress the tree and probably kill it.
https://www.gardeningknowhow.com/ornamental/trees/weeping-cherry/weeping-cherry-growing-tips.htm