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Rose Pests and Diseases in Australia and What to Do About Them

Even though roses are an absolute delight to grow, unfortunately, they’re not without problems.

Roses are one of my all-time favourite plants to grow in my garden. No matter where I’ve lived, I’ve always added a rose bush or two to the garden.

Even though roses are an absolute delight to grow, unfortunately, they’re not without problems.

Here are the most common pests and diseases that you’re likely to encounter when growing roses in Australia.

I’ll also tell you what to do about them including some natural methods that I’ve tried myself.

Aphids

One of the most annoying pests I encounter on my rose bushes is aphids.

These tiny green sap-sucking insects especially love newly forming flower buds and will cause damage to them as they suck all the goodness out of the developing flowers.

Rose aphids 1 | Plant care

Over the years, I’ve tried many different methods to rid my roses of these annoying pests.

I’m also conscious of not using a lot of harmful pesticides because I like to attract and keep insect predators like ladybirds.

In fact, I get rather excited when I see ladybirds in my garden because the nymphs are the ones that will feed on the aphids.

How to get rid of aphids on roses

One of the things I commonly do is put on my trusty pair of gardening gloves and just wipe them off the rose buds with my fingers. Invariably, this results in me squashing many of them.

Another method I’ve used to get rid of aphids is just spraying them off with a garden hose. Although this can work well, you have to be vigilant because the little pests will continue to come back.

Rose aphids | Plant care

I’ve also tried mixing up some dishwashing liquid with water and spraying this on the pests. This is not often as effective as simply wiping them off or blasting them with a hose.

When I’ve gotten a little desperate because the aphids are causing damage to the flowers, I’ve resorted to spraying them with a mixture of white oil and water. Neem oil also works well for this.

Rose spray | Plant care

However, I will only do this if there are no ladybirds around.

Interestingly, in my current garden, we have a lot of wattle birds that come and visit and I was delighted to see a pair of them sitting on one of the rose bushes earlier this year and feasting on the aphids.

So, you could use this experience to plant some natives such as Callistemon near your roses to attract these helpful birds.

Balling

This can be quite common when we get a lot of rain during summer.

It causes the petals of the developing flowers to stick together and the flowers do not form and are surrounded by dried, brown petals.

How to avoid balling on roses

Once this happens to your rose buds, the best thing to do is just remove the buds altogether because you won’t be able to rescue the blooms. 

Although you can’t stop the rain from wetting your flower buds, you can control your own watering and ensure that you only water the soil and avoid getting the foliage wet.

Black Spot

Black spot is a common fungal disease that affects roses. It causes black or brown spots on the leaves and is common in areas of high humidity.

Rose Black Spot 1 | Plant care

The disease will first affect the lower leaves and these will eventually die.

What to do when your rose is infected with black spot

I’m not fond of using fungicides in my garden, so what I generally do is just remove the infected leaves and throw them in the bin. Although unsightly, black spot will not kill your plants. 

Rose Black Spot | Plant care

It’s also important to clean up any infected leaves that have dropped to the ground and also throw these in the bin. This will limit the spread of the fungal spores.

Plus, remember to only water your roses at the soil level and avoid getting the leaves wet.

Two-Spotted Mites

These little sap-suckers can cause distortion to the growing tips of your rose bushes and also the flowers.

Plus, the leaves will become mottled and discoloured and will eventually die.

You can see evidence of two-spotted mites on the undersides of the leaves as fine webs.

What to do about two-spotted mites on your roses

Fortunately, this is not a problem that has plagued my roses all that often. However, what I would do is simply remove the affected foliage to get rid of the mites. 

Rose problems 1 | Plant care

If the problem is severe, you can spray your roses with a mixture of lime sulphur and water. This is one of the few commercial pesticides and fungicides that I use in my garden as it’s a fairly organic product.

You could also spray your roses with white oil or neem oil to get rid of the mites.

Plus, predatory mites that will feed on the pests are now also commercially available and are a great way to keep the sap suckers off your rose or at least limit the damage they do.

White Scale

White scale appears on a rose stem as a cottony or waxy layer that the females produce to protect themselves whilst they feed.

It is a significant pest but can go undetected on roses due to its appearance as abnormal plant growth, allowing it to spread.

You may find that your roses lose vibrancy, show signs of ill health or become worryingly droopy.

If you suspect White Scale on your rose, it is important to inspect the plant and take steps to remove it.

How to treat white scale on roses

The method for correcting scale depends on the severity of the infestation.

Minor infestations can be dealt with by removing the insects and their waxy coating by rubbing with a finger, or by gently scrubbing with a toothbrush. You can also try dabbing the insect with alcohol from a cotton tip before rubbing, to help loosen it.

Dab the affected area with alcohol once the insects have been rubbed off. This will help to clean the damaged area and discourage another infestation.

For a more severe infestation, first remove all infected plant parts non-essential to the survival of the plant.

Put all of the removed material into sealed bags. Spray the remaining parts of the plant and neighbouring plants thoroughly with one of the products described in the section below.

Pay particular attention towards spraying the undersides of leaves and stems in the internal parts of the bush.

Repeat the spraying once a week for three weeks.

Scale will remain attached to the plant even after dying from contact with the spray used. You can remove the dead insects easily using a gloved hand or a toothbrush.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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