What they need(ed) is consistent adequate watering. The ninebark cultivar is also apt to burn in hot sun even if moist, as do many yellow-leaved forms. Probably none are dead, but will take some time to bounce back even if lavished with good care.

Here is a link that might be useful: Horticultural Techniques For Successful Plant Establishment

Interesting. I wonder why the author of this article advises to not amend soil in the hole. I always do.

It was asked:
"Interesting. I wonder why the author of this article advises to not amend soil in the hole."

Because it's up-to-date info.

Research about that practice was done during the late 70s. It was found that roots tend to stay within an amended hole.

The best thing for a woody plant's (tree or shrub) survival and future, is to root into the native soil. So planting it in native soil puts the roots into immediate contact.

"In 1968, a study was begun to determine the 'optimum' amount of soil amendments to use in the planting hole since recommendations varied from 5% to 50% by volume. The optimum amount turned out to be none"

"The reason for the poor performance of plants in small areas of soils amended with organic matter is primarily one of water relations. Peat does hold substantial quantities of water. However, when mixed with soil, it increases the porosity of any soil. Through the process of capillarity (the ink blotter effect), water readily moves from a coarse material to a fine material unless the system becomes saturated. Therefore, the soil amended with organic matter does absorb water readily following irrigation or rainfall but quickly loses most of the water since the surrounding soil has a finer texture and a greater capillary attraction. This movement of water out of the soil made more coarse-textured by the amendment and into the surrounding finer soil occurs very rapidly when the surrounding finer soil is relatively dry as frequently occurs during the summer and fall. During this time of relatively high temperatures and low humidity, the water loss from the top of the plant is very rapid and the limited volume of water held by the amended soil is quickly lost. The amended soil may be sufficiently dry to cause plant stress while the surrounding unamended soil is still quite moist, but because of the textural differences, the moisture will not move back into the amended soil and since few, if any, roots have extended out into the unamended soil, the plant suffers from drought.

If the plant survives the drought conditions accentuated by the soil amendments, the roots will eventually grow beyond the amended soils and little further effect of soil amendments occurs. However, with species slow to develop horizontal roots such as azaleas, the additional moisture stress caused by the soil amendments may continue for several years.

When planting without the use of soil amendments, the roots grow into loosened and aerated soil of the same texture as the surrounding soil, and a textural difference and dry zone does not occur. Even though the soil is loosened in the planting process, the texture of the soil is not changed"

--Carl E. Whitcomb, Establishment and Maintenance of Landscape Plants

Here is a link that might be useful: Lacebark Inc.