Why do the upper leaves of a Duranta erecta plant become blackish?

Incorrect heat, light, moisture, nutrient and pH levels as well as disease and pests can cause the upper leaves to blacken on a Duranta erecta.

Specifically, the plant in question carries the common names golden dewdrop, pigeon berry and skyflower in English and and xcambocoché in Nahuatl. It grows natively throughout Caribbean, Central and North America. It has to receive enough moisture for the upper 3 inches (7.62 centimeters) to retain enough well-draining water for specks of soil to dot a soil probe, but without pooling or waterlogging. Upper leaves that blacken indicate a problem with:

• Incorrect soil pH affecting nutrient intake by the roots;

• Pesty arthropods, bacteria, fungi or viruses;

• Too little or too much heat, light, moisture or nutrients.

Blackening occurring at the top of a plant tends to point to over-exposure to the elements or problems affecting the intake responsibilities of the roots.