My poor impatiens
Impatiens are shade-loving plants. When temperatures are too high and sunlight too strong they can shrivel and die. The rock wall may be heating up and heating up the soil and roots closest to it. The plants further in from the wall look better. I don't see any signs of disease, mostly heat damaged leaves. If not too damaged (and yours don't look badly damaged), watering them well should revive them. Morning light and afternoon shade work best for them.
Impatiens got their name from their tendency to forcibly eject the seeds when they are ripe from the slightest touch. They originated in equatorial Africa.
Impatiens need to be kept well watered. They require moist well-drained soil and benefit from a layer of mulch around them. The mulch helps maintain soil moisture by reducing soil surface evaporation. Mulch also helps moderate soil temperature to keep the roots cooler. To get them to grow taller space them closer together. This article, Impatiens https://pss.uvm.edu/ppp/articles/impatiens.html, has additional information.