When leaves of plants burn the outer edge will dry up and turn brown. The leaves on your Rose of Sharon appear to be losing their green color. There are several things that can cause this problem.

Overwatering or underwatering could cause the leaf problem you are seeing. The symptoms of overwatering and underwatering look similar; the leaves of a plant start to yellow, begin to wilt, and then the leave edges and tips turn red-brown as they die.

The loss of color or yellowing could be an indication of a nutritional deficiency. With a nitrogen deficiency the entire leaf will fade to yellowish-green. With iron and manganese deficiencies the new leaves turn light-yellow between the veins and then it spreads to the entire leaf. This is usually found when the soil pH is alkaline. Rose of Sharon is adaptable to pH, but if the pH is above 7.3 this could be a problem.

Rose of Sharon likes hot weather in full sun to part shade. It grows best in well-drained soils. The leaves of this plant usually do not appear until late spring, but when the soil and air temperatures are above average for an extended period of time the leaves can develop early. For more information on Rose of Sharon see: Hibiscus syriacus.