Oleander (Nerium oleander) is a prolifically blooming shrub that brightens up the landscape in the warm climates of USDA plant hardiness zones 8 through 10. Although the plant is hardy and adaptable, it can develop various problems, including oleander leaf curl. If your oleander leaves are curling, it’s time to troubleshoot some possible reasons. Read on for suggestions.
Leaf Curl on Oleander
When it comes to troubleshooting reasons for leaf curl on oleander, it’s important to start with the basics.
For example, improper watering may be the culprit. During warm weather, oleander should be watered any time rainfall is less than an inch per week. As a general rule of thumb, the shrub benefits from a deep watering once every three or four days. Avoid frequent, shallow watering, which encourages weak, shallow roots. On the other hand, don’t overwater, as poor drainage or soggy soil can also cause oleander leaf curl.
Well-drained soil is also a must for healthy oleander plants. Additionally, a 2- to 3-inch layer of mulch helps keep the soil evenly moist.
Note: An unexpected cold snap can cause oleander problems, including oleander leaf curl.
Additional Oleander Leaf Curl Issues
Problems with curling oleander leaves may be sue to leaf scorch or insect pests.
Oleander Wilt Leaf Scorch
Oleander tends to be relatively disease-resistant, but oleander leaf scorch is a widespread problem in some areas. In fact, the disease is so rampant in certain locales that gardeners are advised not to grow the shrub at all.
Oleander wilt leaf scorch is caused by a bacterium that prevents the plant from effectively conducting water. There is no cure for the disease, which is evidenced by leaves that turn yellow and droopy before dying. Although oleander leaf scorch shows up on one part of the shrub, it usually travels to the roots, then back up through the entire plant. Removal of the plant is the only recourse.
Oleander Leaves are Curling from Pests
If you’ve resolved any watering problem and you’ve determined the problem isn’t oleander leaf scorch, be on the lookout for bugs, as certain pests can cause oleander leaf curl.
Look closely for aphids, scale, or mealybugs. All three are relatively easy to control with insecticidal soap or horticultural oil. However, don’t spray the plant on hot days or when the sun is directly on the leaves as you may do more harm than good.