Why are My Jacaranda Leaves Turning Yellow?
Jacaranda is a genus of 49 species of flowering plants native to tropical and subtropical areas. They thrive in full sun and sandy soil and once established are fairly drought tolerant with few insect or disease issues. That said, they can, especially young and newly transplanted trees, begin to turn yellow and drop leaves. Young plants are also more susceptible to cold temperatures than mature trees. Mature plants can survive down to 19 degrees F. (-7 C.) while tender young trees may not survive such temperature dips. If your region gets this cold, it is advisable to move the tree indoors where it will be protected from the cold. If the jacaranda has yellow leaves due to a lack or surfeit of water, there are a couple of ways to try and treat the problem. First, you need to identify if the issue is too much or too little water. If the jacaranda is stressed from too little water the leaves yellow, wilt, and drop prematurely. Those getting too much water are more likely to have smaller than normal leaves, branch tip die-off, and premature leaf drop. Overwatering also leaches minerals from the soil, which may be a factor with a sick tree.
Treating a Yellow Jacaranda
During the spring and summer months, jacaranda should be watered slowly and deeply once every two weeks. During winter when the trees are dormant, water just once or twice. Don’t water at the base of the trunk but rather around the dripline where rain naturally falls from the outer branches. Watering at the trunk may foster fungal infections. Apply a layer of mulch around the tree as well to retain moisture and keep roots cool; keep the mulch away from the trunk, however. On the note of fungal diseases, be sure to plant the tree so the crown is not immersed in a hole that might hold water, resulting in crown rot. If the problem does not seem to be related to irrigating, it might be due to excessive fertilizing. Overfertilizing may result in a jacaranda that has yellow leaves, specifically yellowing leaf edges and dead leaf tips. This is because of an excess or buildup of minerals or salts in the soil. A soil test is the only sure way to diagnose this problem. Folks that keep their jacaranda indoors during winter months due to chilly temperatures need to be sure to harden off the tree before moving outside for the summer. This means moving it outside into a shaded area during the day and then back in at night, and then into an area with morning light and so on for a couple of weeks, gradually exposing the plant to full sun. Lastly, if a yellowing jacaranda is a recently transplanted sapling, the issue may be transplant shock. Try slowly watering in regular applications of either a B vitamin or Superthrive every few days until the tree looks better and has established.
