Hibiscus is a wonderful choice for most garden themes and a wide range of climates from USDA hardiness zones 4 to 11. They’re easy to maintain, plus the edible flowers bring all sorts of pollinators
But like all good things, hibiscus plants aren’t perfect and may suffer from diseases like rust. In this article, we will provide you with effective ways to control Hibiscus rust. Read on for more information.
What Does Hibiscus Rust Look Like: How to Control It?
A lot of plant diseases look similar at first glance. However, rust is a rather distinctive one. You know what to look for.
What Is Hibiscus Rust?
Rust is a fungal disease that can affect a wide range of plants. It gains its name because of the distinctive brownish-orange spots on an infected plant’s leaves, making it look like it is literally rusting.
Hibiscus rust is caused by the fungus Kuehneola malvicola. However, hibiscus plants are also affected by mallow rust, AKA hollyhock rust, which is caused by the fungus Puccinia malvacearum.
These fungal strains affect many plants, and one stain may affect plants that the other one doesn’t
Otherwise, these two types of rust have the same symptoms and treatment, so we won’t make any distinctions between the two.
What Does Rust Do?
Rust is a parasitic fungus that burrows its way into a plant’s leaves. Once there, rust-colored pustules begin forming on the underside of the infected leaf.
These pustules eventually burst and release their spores, easily carried by the wind.
Meanwhile, the upper surface of the leaf will develop slightly larger spots that appear a little more yellow in hue.
These spots don’t produce spores but interfere with photosynthesis and make the plant look less attractive.
Infected leaves can become necrotic, suffer stunted growth, or prematurely fall off.
If not treated on time, rust can severely weaken plants and spread throughout a garden at a rapid pace.
Rust can survive on a plant for years unless addressed.
Treating Hibiscus Rust
Dealing with rust can be both relatively easy and incredibly frustrating due to how easily it spreads.
Try to thin out any nearby plants to reduce the risk of spread and lower humidity levels.
Here’s what you need to do:
- Grab a pair of sharp, sterile shears and carefully prune away any parts of the plant showing clear signs of infection.
- Be sure to sterilize your tools between each cut and avoid touching any other plants until you have thoroughly scrubbed your hands and arms to ensure you don’t cross-contaminate.
- Dispose of your cuttings by putting them in a sealable bag and burning them.
- Once the visible damage is removed, you will need to treat the plant.
- Use a sulfur-based fungicide and spray the entire plant according to the instructions on the label.
Be warned, treating plants with sulfur-based products when the temperature is above 85° degrees Fahrenheit can result in further damage to the plant, so be sure to pick a day when it’s cooler or treats your hibiscus in the evening as things cool off.
Preventing Rust On Hibiscus
Prevention is the best way to keep your plants healthy and can prevent many headaches and heartbreak.
The first step is to remember that grouping plants together will increase humidity levels.
High humidity increases the risk of fungal infections, so try to balance grouping and an acceptable humidity range.
Likewise, watering can increase the risk of rust and related diseases.
Always use a reliable watering method, such as the soak and dry method, and never water your plants from overhead.
Doing so can leave water droplets in places where they dry more slowly.
Third, consider using a neem soil soak.
Neem soil soaks absorbed by your hibiscus roots become a systemic insecticide that protects the plant for up to 22 days.
Not only does neem oil kill many garden pests, but it can also fight and kill fungi and some bacteria that invade the plant.
As neem is non-toxic to humans and pets when used properly, you can safely treat your hibiscus every 2 to 3 weeks with the soil soak as a preventative.
However, neem oil will not defeat a full-blown infection on its own.
Finally, keep things clean.
Remove all leaf litter and debris to reduce the risk of rust gaining a foothold.
Only buy hibiscus plants from reputable suppliers to ensure they’ve had a full inspection and preventative treatments.
If growing hibiscus in a container, isolate it at the first sign of an infection to minimize the spread risk.
And when handling any plant, make it a habit to wash your hands and sterilize any tools to prevent cross-contamination.