I planted Japanese kerria shrubs several years ago. They were doing fine until last summer. The leaves were rusty brown and this spring the stems were dead. A few new shoots did sprout this season. We did not water the plants last year but did start watering our landscape this summer. Are the plants dead?
Drought, like we experienced last summer and this year can cause yellowing, browning and even death of leaves and stems. Water plants thoroughly whenever the top few inches of soil are crumbly and slightly moist. Stressed plants, like your kerria, are also more subject to winter injury. Remember the below zero temperatures and lack of snow in January 2009? That resulted in lots of dieback and death on a variety of plants. Remove any dead growth and wait for the new growth to fill in. Proper watering during extended dry periods, time and patience on your part should result in some nice looking shrubs next season.