Hibiscus plants are cherished for their looks but aren’t always the easiest to care for. Several insect pests love infesting these plants, and the usual solutions aren’t always an option.
In particular, hibiscus is highly sensitive to several chemical insecticides, including chlorpyrifos, lannate, and malathion.
The wrong insecticide can cause severe burns to your plant and may not even be all that effective.
In the realm of natural solutions, organic neem oil for plants is one of the most reliable.
Neem oil is the product we recommend. But even this natural ingredient can cause problems with some plants, so is it safe to use Neem oil on hibiscus?
Can You Use Neem Oil On Hibiscus
While there is a chance your particular plant may be oversensitive, neem oil is generally safe for use on hibiscus plants.
Here’s how to use it and a few tips on safety around this beloved garden ornamental.
The Three Types of Neem
100% percent cold-pressed raw neem oil comes straight from the tree and contains Azadirachtin, a powerful insecticide.
This version of neem works when ingested, where it mimics the natural hormones of the target plant pest.
This leads to loss of appetite, interrupting the growth cycles of nymphs, and infertility in adults.
Raw neem is generally too powerful for topical application and is best used as a soil soak.
The byproducts of creating neem oil are known as neem cakes.
These solids are often used as fertilizer and contain a 4-1-2 NPK ratio and fatty acids and several micronutrients.
Using neem cakes can be as simple as breaking one up and mixing it with soil or water as directed on the package.
More on Neem Cakes and Its Use
The third type of neem is results from removing the Azadirachtin and is known as clarified hydrophobic neem oil.
This form of oil contains only trace amounts of Azadirachtin, ranging from .5 to 3% percent.
This is the form of neem most often used in foliar sprays due to its more gentle nature.
It affects insects directly by clogging their airways and causing them to suffocate.
While less effective overall, it works more quickly and dissipates within 45 minutes to 1 hour, leaving behind no residue.
Treating your Hibiscus with a Neem Foliar Spray
Neem oil spray is a great option for a natural foliar application and leaf shine.
Making the spray is simple and requires only three ingredients.
Gently mix 1/3 teaspoon of liquid dish soap (Dawn) or pure castile soap into a quart of warm water.
This creates an emulsion, breaking the surface tension in the water and allowing it to mix with oil.
Next, add one teaspoon of clarified hydrophobic neem oil and pour the mixture into a spray bottle.
Be sure to test a small part of your plant 24 hours before making a full application to ensure your hibiscus isn’t allergic or sensitive to the treatment.
Spray every part of the plant thoroughly, paying special attention to crevasses and the undersides of leaves where infestations are most likely to occur.
Repeat this process every other day for 14 days or until any infestation is gone.
You can also apply the foliar spray once every two weeks as a preventative.
Treating Your Hibiscus with a Neem Soil Soak
The recipe for a neem soil soak or drench is almost identical to that of a foliar spray, except it uses 100% percent cold-pressed raw neem oil instead of the clarified neem.
Pour 2 to 3 cups of the soil soak onto the soil around the plant, being careful not to get any on the plant itself.
Soil soaks are far more effective, as the plant absorbs some of the neem, and it becomes a systemic insecticide.
Any insect that bites into or pierces the plant will ingest the neem oil, destroying the infestation literally from the inside.
Soil soaks also have the added benefit of helping to treat root rot, kill grubs, and help protect against fungal and microbial infections.
The oil remains in your hibiscus for up to 22 days and may be applied every three weeks as a preventative.
Hibiscus Treatment Tips
Always be sure to test a small area 24 hours before using neem on the entire plant to ensure the plant will tolerate it.
Treat outdoor garden plants at dusk or dawn to prevent exposure to beneficial insects. Avoid spraying flower buds if possible.
Avoid spraying near beehives or water features containing aquatic life, as neem is slightly toxic to fish, and droplets may be carried on the wind.
Always follow any product label instructions on the package, as the oil may vary slightly between companies.
When using clarified neem, aim for a lower Azadirachtin content unless dealing with a particularly bad infestation, as higher percentages increase the risk of a plant reaction.