General gardening topics

Treating and preventing rust on plants such as roses, vegetables, perennials, shrubs and fruit

Last updated on May 5th, 2022

Our site is reader supported, this means we may earn a small commission from Amazon and other affiliates when you buy through links on our site.

Rust is one of the most common fungal diseases for any garden plant. Whether you have vegetables, fruit, grasses, herbaceous plants, trees, or shrubs, they are susceptible to rust, especially roses. Rust is often very unsightly and typically reduces plant health. In the most extreme cases, they can kill your plant, but this is fairly rare.

Rust is a kind of fungal disease and the most commonly affects the leaves on your plant, however, occasionally it can affect the stems, the flowers, and even the fruit. This fungus is often yellow, red, or even grey colour depending on the species and the type of spore that is being produced. Some rust diseases have very complex life cycles with up to five different types of spores that can spread in different ways, so it’s important that it’s treated at the first signs to prevent it from getting out of control.

Rust on a pear tree

How to spot the symptoms of rust

Given that there are many species there are different symptoms, this is dependent on the species and the plant it is impacting. You might notice pale copper coloured leaf spots developing on your leaves, sometimes on the underside, creating somewhat raised structures and these are the spore-producing pustules.

These pustules are often found on the lower surface of the leaves and they produce huge quantities of microscopic spores that can spread very far and make their way over the entire surface of your plant if you don’t control them.

Rust fungus on rose bush leaves
Rust on a rose bush

The pustules can be black, white, brown, yellow, or orange, some take on a very rusty brown colour which is what lends the disease its name. You might even notice there are dozens of these coloured pustules on a single leaf. Severely impacted leaves will eventually turn yellow and fall off.


Treating plants with rust

If you have noticed these symptoms on your plant, fast action is imperative. Given the high number of microscopic spores that can exist on a single leaf, infestation and spread happen at a rapid pace.

Each type of rust disease your plant has will have specific levels of preventative action and control. But in general, treating rust on your plants involves picking off the affected leaves first and foremost, as soon as you see them and then spraying with a fungicide to help prevent it from spreading. This is the perfect remedy for a very small infection. If you only have a few leaves that are affected, get rid of them and remove any that have already fallen off so that the spores can’t travel.

Treating plants that are heavily invested with rust

If you have a larger number of affected leaves you might not be able to pick them all off. Any diseased or dead material should be removed at the end of the growing cycle because many of the spores for rust diseases will overwinter and remain very resilient during that time, waiting until spring to strike again.

If you have rust on roses it can be worthwhile to try cutting the rose back and removing all the foliage and then spraying them with a fungicide. The problem with some other plants is that it can do more harm than good to cut the plant back hard, however, roses usually recover quickly.

How to help prevent rust in the first place

Non-chemical treatments are best done as a preventative measure. You want to avoid excess nitrogen fertiliser, remove any diseased material as soon as you see it, give your plants proper airflow, and avoid watering anywhere but the base of the plants.

Treating edible crops such as fruit and vegetables

If you have edible crops, fruits or vegetables, there are currently no fungicides that will control rust diseases safely. If you have any other ornamental plants, you can use fungicides with tebuconazole or triticonazole. If you are growing ornamentals with a lot of foliage and flowers they might be sensitive to damage by certain fungicides. This is why you should always read the labels prior to use.

Wheat plant showing the symptoms of yellow rust

Recommended fungicides for ornamentals plants and roses

Last update on 2024-12-03 / Affiliate links / Images from Amazon Product Advertising API

Welcome to my site, my name is John and I have been lucky enough to work in horticultural nurseries for over 15 years in the UK. As the founder and editor as well as researcher, I have a City & Guilds Horticultural Qualifications which I proudly display on our About us page. I now work full time on this website where I review the very best gardening products and tools and write reliable gardening guides. Behind this site is an actual real person who has worked and has experience with the types of products we review as well as years of knowledge on the topics we cover from actual experience. You can reach out to me at john@pyracantha.co.uk

Write A Comment