When you spot something that doesn’t look quite right on your plants, it can be devastating. What the heck is that weird coloring? Is that plant rust?! What do I do!?!
Noticing something awry on your previously pristine plant is stressful. Treating the problem takes time and effort and requires a bit of know-how on your end.
So how do you deal with rust on your plants? Is it possible to successfully restore plants to their original condition? Read on to find out more about this all too common disease.
What is Rust?
Here’s the deal, there are thousands of species of rust that can affect your garden or indoor plants. Different types of rust attack different varieties of plants.
Common rust, however, is well… a common species that affects a wide variety of plants, including edibles like beans and tomatoes. It’s more likely to affect mature plants than it is younger ones.
Rust is an unattractive fungal disease that can stunt growth and reduce the healthfulness of your plants, but it rarely kills crops outright.
However, if you leave the disease to run its course, your plants will decline in health and may not produce as expected – edible plants in particular. On top of that, if you sell your plants at the market, no one wants to buy your leafy greens if they’re covered in rust.
That’s why it’s best if you address a rust outbreak straight away.
How Does Plant Rust Spread?
Rust thrives in situations where it’s warm and moist, so it’s a common disease in climates with a hot, humid gardening season. If you live in an area that receives a lot of rain, rust is likely a common garden problem.
It’s possible for plants to contract rust in hot, dry climates, as well. Gardens with poorly draining soil or plants that are overwatered frequently are susceptible to the disease.
Rust is spread via fungal spores. The spores are transferred to plant material either by blowing wind or by splashing water.
The fungal disease spreads easily, which is why it’s so important to address a rust infestation when it appears in your garden. Other plants located near an infected plant will inevitably contract the fungal infection.
Signs of Rust
The main signs of rust typically appear on plant foliage. Common rust often starts out as raised spots, sometimes white in color. Eventually, the marks transition to a reddish hue – hence the name rust! Spots may turn black in some cases.
Another common symptom that appears on foliage is raised bumps. They appear in a variety of colors, including brown, yellow, or orange. The bumps usually appear on the underside of infected leaves.
In severe cases of rust, leaves crumple, wilt, and fall to the ground.
Which Plants Are Vulnerable to Rust?
All sorts of plants are vulnerable to this fungal disease. There are so many species of rust that it’s pretty much impossible to list all of the plants that are susceptible to the disease. In fact, it’s even possible for rust to infect your lawn.
It’s an extremely common garden affliction. Chances are, you’ve dealt with this disease, even without knowing it.
Plants that are particularly susceptible to rust include:
- Roses
- Hollyhocks
- Snapdragons
- Daylilies
- Beans
- Tomatoes
- Corn
- Grasses
Plants infected with rust likely won’t die, but their health will decline, and they’ll appear a lot less healthy than other plants in your garden.
Severely infected plants may lose leaves. They may also grow a lot slower than comparatively healthy plants in your garden.
How to Prevent Rust
Here’s a breakdown of all the strategies you can use to avoid rust from becoming a problem in your garden.
Buy Rust-Resistant Varieties
When browsing seed catalogs or picking up new seedlings at your local nursery, select disease-resistant varieties whenever possible.
Clean Your Garden
Avoid leaving behind debris in your garden, especially if you live in a wet climate with lots of rain. Splashing water easily transfers disease spores to foliage.
To lessen the chance of spores getting onto your plants, keep the area underneath your plants clean. Use mulch to protect your plants from rust spores living on the topsoil.
Prune Appropriately
Carefully prune bushy plants to ensure proper air circulation. Avoid planting things too close together, as well. Regular weeding also helps improve air circulation and reduces the chance of disease spread.
Water Plants Carefully
Don’t use overhead watering methods (spray hose nozzle or sprinklers, for instance). Use drip irrigation instead to prevent foliage from getting splashed with water. Try not to overwater.
I know, watering is a tough balancing act. But watering too much encourages a humid environment, and rust fungal spores love humidity. If overhead watering is unavoidable, water your plants early in the day so that the leaves have enough time to dry and don’t stay damp overnight.
Plant in Areas with Proper Drainage
When choosing a spot for your garden, avoid waterlogged areas where water pools after a rainy day.
Fertilize Appropriately
Avoid overdoing it with high nitrogen fertilizers, which can produce susceptible foliage. A nutrient imbalance is also likely to cause soil health issues that can exacerbate diseases.
Use Fungicides
Apply copper fungicides. If you’ve dealt frequently with rust in the past and want to implement an active strategy for preventing infection on vulnerable plants, use products like copper sprays.
You can also use copper sprays to treat minor rust infections. They must be re-applied every week or so to be effective. Other commercially available anti-fungal products are also an option. Most are safe to use around edible plants, but always carefully read labels to be sure.
Use Good Hygiene
Implement good garden hygiene practices. Rust also spreads via the use of dirty garden tools. Clean your shovels, spades, and weeding implements regularly to avoid spreading rust around your garden. The easiest way to disinfect tools? Use a mixture of diluted bleach.
How to Treat Rust
If your plant is infected with rust, your first action should be to remove diseased plant material. Pick off affected leaves and throw them in the trash. Don’t compost them, you’ll spread the rust wherever you use your compost.
If removing infected plant material doesn’t solve the problem and rust damage continues to appear on your plants, commercial fungal treatments are your next best bet. Try applying copper fungicides or sulfur dust to affected leaves. Always read packaging thoroughly to ensure you’re using it safely.
Fungicides containing sulfur or copper combat rust by altering the pH of the surrounding environment (in the case of rust, the pH of the foliage). The fungus can no longer survive when the pH balance is out of whack.
When using fungicides, spray the affected foliage as soon as you spot signs of rust. Repeat application every week or so. Apply these types of sprays in the early morning or evening to prevent leaf burn.
Rust Won’t Stand a Chance
While it may be extraordinarily common, plant rust is always an unpleasant surprise. That doesn’t mean it can’t be dealt with. Prevention is best, but the right techniques can help you eliminate the disease.
Have you ever dealt with rust in your garden? Which plants were affected? How did you treat the common fungus? Let us know in the comments.
