Dead Leaves on a Cassia Splendida

Frost Damage

• The most common cause of dead leaves is exposure to freezing winter temperatures. Cassia splendida is best grown in USDA Zones 9 and 10 where temperatures below 32 degrees are infrequent. In Zone 8 it will experience colder weather that damages leaves and stems. Ordinarily the plant will resprout from the base once warm weather resumes in the spring. Prune back the dead portions of the plant in late winter when it is obvious which parts are dead.

Shallow Root System

• Cassia splendida does not have deep roots. Damage can occur to shallow roots from impaction or soil disturbance, causing lesser uptake of water which may cause leaf dieback. If the branch containing dead leaves is also dead, prune it off. Otherwise, as the root system recovers, the plant will resume normal growth.

Root Rot

• Plants are short-lived, normally becoming senescent or ready to be replaced at around 10 years old. After a decade, vigor declines and the plant grows more poorly and slows in flower production. It is also more susceptible to root rot at this time, which can cause leaves to die.

Drought

• Shallow roots dry out quicker since they are closer to the soil surface. Young plants in their first year or two in the landscape are more susceptible to drying out than older established plants. When drought conditions occur, with no rain for several weeks during the active warm weather growing season, watch the plants for wilted leaves and provide extra water as needed so the leaves don't get damaged and die. In older established plants, water needs are average. If prolonged drought occurs, especially in summer when large plants are growing vigorously, water the plant if leaves begin to wilt.

Seasonal Leaf Loss

• Cassia splendida is semi-evergreen, with some of the leaves turning yellow and falling off after flowering. This is normal, and is actually an attractive feature of the plant, giving colorful autumn foliage.