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Common Diseases that can affect your Garden rose trees and rose bushes

The most severe fungal diseases are Mildew, black spot and rust. Despite some being more common diseases than others, you should always keep your roses in the best conditions.

Contents Table

You may notice that some varieties are described as “disease-resistant”, which means they will remain free from attack under ordinary conditions, but under epidemic conditions, preventatives will be necessary.

These varieties are resistant, not immune! Checking out the care and maintenance of your roses is an excellent option to help prevent diseases, as a healthy, vigorous plant is less susceptible to diseases.

Rust Disease

Although rust is not common when this disease strikes, it is often fatal! Rust is most likely to take over when there is typically a shortage of potash. 

A cold spring followed by a dry summer and a hard winter will also encourage this disease to form. Rust disease is typically seen in mid-to-late summer and autumn.

How to spot if your roses have Rust Disease

The solution to Rust Disease

In extreme cases, and in particular, if left untreated can kill your plant; this is due to it reducing the plant’s vigour.   


Mildew is the most widespread disease amongst roses and caused by the fungus Podosphaera pannosa. Closed-in conditions, dryness of roots, poor feeding, and hot days followed by cold nights are a few examples of why your roses may contract Mildew. 

How to spot if your roses have Mildew

The solution to Mildew

Black spot (Diplocarpon rosae)

Black spot is the most serve disease your roses can have. It spreads rapidly if not treated at the first chance. Heavy infestations will spread to the leaf buds and then onto the stems; this can cause the vigour to be significantly reduced, eventually dying back. 

Potash shortage and warm, wet weather in the summer can invigorate this disease. 

How to spot if your roses have Black Spot

The solution to Blackspot

Canker – (Coniothyrium)

Canker is a pathogenic fungus that will affect the stems; it enters the stems by a wound caused by an insect or disease or mechanical damage; therefore, it’s good to watch out when hoeing.

Although not typically complicated by the fungus disease, it can be pretty damaging whilst also negatively impacting the appearance of your roses. 

How to spot if your roses have Canker

The solution to Canker

If left untreated and the Canker enlarges and encircles the stem, the whole growth above the diseased area will sadly die.


Die-back is not a specific disease; it can be caused by frost damage, Canker at the stem’s base, waterlogging, Mildew or black spot. 

Lack of potash, calcium, phosphates and boron are all common causes for die-back and can present themselves at any time of the year, so it’s always good to be on the lookout. 

How to spot if your roses have Die-back

The solution to die-back

Unfortunately, there are no fungicides currently that will cure die-back, and the best way to protect your rose from die-back is to ensure that they have the best planting conditions you can check out here. Below are a few preventatives for you to keep in mind;  

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