Answer: Dry soil is difficult to dig, and the plants roots will have an equally hard time trying to grow through it. Good soil preparation is critical to planting success, so this is probably not the best time to be planting.
If you really want to prepare the soil, you would need to water it a day or two ahead of time. Apply it very slowly and make sure it soaks down deep, about a foot down for planting shrubs or trees.
Also, mid summer heat is the most stressful time frame for planting and transplanting.
In my experience, it is better to wait until early fall to plant. Hopefully, seasonal rains will soften the soil so it can be prepared and then the rains will also help keep the soil evenly moist while the plants begin to establish.
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