Leaf scorch is the reason why your Oleander plant is dying. Leaves turn brown and appear like they’re scorched, eventually, the plant dies. Oleander knot disease is another lethal disease that has no cure.
Nerium oleander, commonly called Oleander or Nerium grows worldwide. The plant is grown in gardens for its beautiful flowers.
The plant is highly toxic to humans. It’s still grown for landscaping purposes. Let’s see what diseases affect the plant and see how to fix them.
Why is my Oleander drooping?
Your Oleander plant is drooping because it didn’t get enough water. Drooping leaves are the first sign of underwatering in most plants.
Oleander leaves drying up
Leaves become dry and droopy when the Oleander plant is underwatered. This most commonly happens in the summer months.
Feel the soil around your Oleander plant with your fingers. If it feels bone dry then underwatering is probably the culprit.
To fix droopy Oleander
It would be best if you started watering your Oleander plant deeply and more often in the summers. Do not let the soil go bone dry.
Feel the soil and water when the top two inches of the soil goes dry. Watering the plant regularly according to a schedule helps avoid such situations.
Oleander leaves curling (Oleander leaf scorch)
Your Oleander leaves are curling due to a bacterial disease called Leaf Scorch. This is quite common in Oleander plants. Oleander leaves also get curled when certain sap-sucking insects like Aphids, Spider mites, and Scale infest the plant.
What does oleander leaf scorch look like?
Leaves become curled and they turn yellow. Eventually, entire leaves get scorched, thus looking brown. The leaves become dry as you can see in the video below.
The bacterial pathogen that infects Oleander spreads with the help of Leafhoppers. So, if you can keep Leafhoppers in control, Leaf Scorch can be prevented.
How do you treat oleander leaves scorch?
The disease is so stubborn that gardeners in some areas don’t grow the bush at all. There’s no known cure for Oleander leaf scorch.
The disease starts in one part of the plant and slowly spreads to the entire plant. The disease deters the transportation of water.
You may want to dispose of the infected plants/plant parts as you don’t want a widespread problem in your garden.
Oleander leaves turning brown
The main reason why Oleander leaves turn brown is the Oleander Leaf scorch. The leaves turn brown and look like they’ve been burned.
We already discussed Leaf Scorch above. Infected plants can not be cured. You just need to dispose of the infected plants and the soil that’s beneath such plants.
Oleander brown leaves after winter
Oleander leaves turn brown due to frost damage. This especially happens in the northern end of the shrub’s range. Frost damage can be minimized if you detect it early.
Don’t plant your Oleander in a windy place. If you live in an area with harsh winters, don’t plant your Oleander in the South/South-West side of the building.
You can also take your Oleander plant indoors to let it overwinter. Give it abundant water and mist often to provide the humidity it needs.
Why are my Oleander leaves turning yellow and falling off?
Oleander leaves turn yellow and fall off due to improper watering. Both overwatering and underwatering cause the leaves to turn yellow.
Underwatering
As we discussed earlier, underwatering causes drooping in Oleander leaves. The leaves eventually turn yellow.
The leaves turn yellow but dry. This is what differentiates underwatered plants from overwatered plants.
Do not let the soil beneath the plant go bone dry. Check with your fingers if needed and water the plant if it’s dry up to two inches or more.
Oleander Overwatering
If you water your Oleander plant more than needed, the leaves turn yellow too. Such yellow leaves of Oleander eventually fall off the plant. Oleander plants are usually drought-tolerant.
Oleander plants need one inch of water per week to thrive. If you water them more than needed, the plant runs into issues like root rot.
Water your Oleander plants properly and they should recover in no time.
How often should I water oleanders?
Water your Oleander plant once a week. An inch of water per week is enough for the plant to thrive. Make sure you’re watering only the soil, don’t wet the leaves.
Check the soil with your fingers if you’re unsure when to water the plant. Water only when the top 2-3 inches of the soil is dry.
Oleander leaf spot
Various types of fungi can cause spots on the leaves of Oleander plants. Yellow, Brown, or White-colored spots form on the infected plant’s leaves.
Yellow-bordered spots are caused by a fungal pathogen called Stemphylium. Such spots enlarge and become blotches.
You can prevent leaf spot diseases in Oleander by keeping the leaves dry. Wet leaves harbor and encourage the growth of fungi.
Treating oleander fungus
Dispose of the infected leaves to prevent the spread of infection to other plants. Improve air circulation by pruning your Oleander.
The plant will recover eventually if you just take good care of it.
Oleander knot disease
Oleander knot disease/Gall disease is caused by a bacterial pathogen. This pathogen enters the plant through wounds.
Plants infected by this plant develop galls or knots on the leaves, flowers, and stems of the Oleander plant.
Oleander knot disease spreads after the cool, damp springs. The bacterial pathogen enters the plant via wounds or winter damage.
The infection also spreads via contaminated water, tools, or human hands. So, be careful when you handle infected plants.
There’s no cure for these bacterial diseases. Treat the plants carefully and the plant will recover itself if it can.
To control
You can take some preventive measures to avoid running into this situation.
- Do not let the leaves get wet. Overhead sprinklers wet the leaves thereby harboring and encouraging the growth of these pathogens.
- Planting your Oleanders in full sun and watering them regularly is crucial to avoid such diseases.
Oleander mildew
Powdery mildew does attack the Oleander plant. Infected plants’ leaves as you probably already guessed, turn whitish.
The leaves look like someone dusted them with talcum powder. This powdery layer first begins on the upper side of the leaves eventually moving to the undersides.
Infected flower buds shrivel and do not blossom. The leaves of the infected plant turn yellow eventually and fall off the plant.
Prevention
- Do not wet the leaves of your Oleander plant.
- Plant your Oleander in a well-ventilated area. Clear any plants that surround your Oleander to facilitate this.
- Clear the debris near the plant as early as possible to prevent an infection.
Control
- Prune off any leaves of the plant that show signs of fungal growth.
- If the infection is severe, dust the plant with sulfur powder. This should get rid of the fungal infection for good.
Oleander White Fungus
False Oleander Scale is one of the most common insect pests that infest Oleanders. Numerous white specks or blurry spots are seen on the leaves of the affected Oleander plant. This is not a fungal disease, just an insect infestation.
Tufts of these insects can be found on the leaves, feeding on the sap of the plant. The individual spots are 2 to 3mm in diameter and are usually seen on upper leaf surfaces.
You can get rid of the infestation by pruning the affected branches regularly. Insecticides won’t work on scale insects due to the outer protective layer.
Scale infestations can pave the way for fungal growth called ‘Sooty Mold’. Fungal pathogens grow by feeding on ‘Honeydew’, secreted by Scale insects.
How to revive dying Oleander?
Follow the below cultural practices to revive your dying Oleander.
- Improper watering can lead to a lot of problems. Fix the draining ability of the soil/potting mix by adding Perlite to it. You don’t want the soil to hold too much water for a long time.
- Oleander leaves turn yellow with brown edges when the plant is affected by Bacterial Leaf Scorch disease. The disease spreads via Leafhoppers, so you can control the disease by controlling Leafhopper populations.
- Don’t let the leaves get wet when watering the plant. Diseases like Oleander Knot spread when contaminated tools/water is used on healthy plants.
- You need to cut off the infested branches of Oleander as soon as you see white blotches/scale insects on the plant. Insecticides don’t work on Scale insects.
Happy Gardening 🙂