To spray, or not to spray, that is the question

‘Hi, I notice you receive many a question on what sprays will sort frangipani rust and although your advice on using natural products and good house-keeping to combat the rust is good advice, in my experience using your advice only slightly helps in trying to eradicate the problem which I have been trying to do over the past 4 years to date. The trees are no better off than when I first started etc.


However, I have finally managed to completely eradicate the rust problem and haven’t had any frangipani rust problems for the past 3 months and although you may not approve of what I used, or how I obtained the spray, however through desperation felt I really had no choice but to do so, the following is what I used.


At the beginning of last year on a visit to Australia I purchased the following: Scorpio, which proved to be the best, very expensive and was very hard to obtain.Rust Rid, although takes longer is extremely good and will completely eradicate the rust as the diluted mix its poured onto the soil at base of trees, so is eventually absorbed into the tree itself and in time completely knocking the rust on the head. Rust-Rid can also be sprayed onto the leaves etc. Triforine, also extremely good product and “almost” eliminated the rust.


I won’t bore you with the process as to how I came to these recommendations, but over past 12 months I carried out many experiments and I can safely say I have finally eradicated frangipani rust from all my trees. Your readers may be interested in this? Barry’

Thank you for the contribution regarding the dreaded frangipani rust, much appreciated – hence the reason I have passed it on. Mancozeb or anything containing sulphur are also highly recommended among the commercial applications. Neem oil is also effective, and whilst organic is nevertheless still very toxic.

Since frangipani is a mainstay of the tropical garden I regularly receive questions about its care and maintenance. Whilst aware of the chemical controls, personally I advocate organic or the least toxic solutions if possible. But it’s not for me to play gatekeeper (knowledge is power) and I’ll let readers weigh up the pros and cons to decide their own preference to toxic chemicals or organic solutions.

Yes, it is true that in most cases the homemade remedies will require a few minutes preparation and more diligent follow up, and since everyone seems to be time poor these days I can see the attraction in reaching for the bottle of poison, and if it’s the difference between saving your tree or letting it die then by all means do what you have to do – I just like to keep you informed on all options.

Back in the 80s when I was a mini green thumb I had a veggie patch and loved watching a popular weekly Australian gardening show ‘Burkes Backyard’ of which I’m sure many of the ‘Aussie’ expat readers are familiar with. Fast forward to the present, Burke has recently endured a scandal of his own in the wake of the Weinstein affair but it’s not for me to judge and that’s not even the point of why I bring this up. Along with the show Burke released numerous books and a monthly magazine aligned with the TV production on all things gardening. Whenever readers would have a question about bugs, pests, plant disease etc a chemically toxic solution was always the answer, always!

Spray with this or that, usually a Yates product or one of the other well-known brands that would co-incidentally have full page ads littered throughout the magazine. Organic solutions were but a mirage, within the parched landscape of the Bayer chemical range. I used to think to myself even as kid that this is total BS there are other ways you can do it. Yet the ‘guru’ who everyone looked to proclaimed in an authoritative tone that, ‘This is truly the only way!’

As a teenager I came to realise that it’s all about commercial agreements and narrow solutions. Kind of like how the doctor prescribes you pills for your blood pressure and lets you keep on drinking beer and eating hamburgers…when he could really tell you to fix your diet and there’d be no need for the pills <unfortunately this also doesn’t fit within the commercial narrative of what has ostensibly has become the ‘business’ of health care, it makes me suspicious as to how much they really do ‘care’? >


Which brings me back to Hippocrates and the saying, ‘let food be thy medicine and medicine be thy food’ which is so true and the reason why I believe it’s advantageous to grow as much of your own food or buy organic where possible. I can’t accept that fruit and vegetables sprayed with poison are going to be just as good for you as the naturally grown type. I digress [end rant here].

At the heart of why I bang on about organic is that there are already enough choices, advertisements, garden gurus and hardware outlets advising and giving you the toxic route. I’m just here to offer alternatives and then you can decide. Indeed, on many occasions an infestation of bugs or fungus may be so severe that chemical treatment is your only option, there is no judgement here, just remember toxic chemicals have consequences – that reminds me of another famous quote: ‘The true meaning of life is to plant trees under whose shade you do not expect to sit.’

In terms of spraying chemicals around the environment with reckless abandon, we may not have to deal with the consequences right now, but somebody will eventually, sort of an antithesis to the quote above.


Harm Reduction

Frangipani rust thrives in a moist or humid environment, and this factor combined with the ease at which it spreads via spores on the wind from neighbouring properties deems it notoriously difficult to control. Poor growing conditions such as a waterlogged soil can also contribute, make sure your soil is well drained and plants well ventilated. By and large though, in the wet tropics plant fungus comes with the territory. Yep, unfortunately you must take the bad with the good!

As for organic solutions, the first step is the timely removal of affected leaves at the first signs, which may on its own solve the problem. Improving air circulation around plants may also help. The need to spray only occurs once the problem is raging out of control.


Baking Soda

Mix a few tablespoons of sodium bicarbonate, bi-carb soda or baking soda (all the same thing by another name) with 1L water, a few tablespoons of cooking oil and a dash of dish soap. The oil allows the spray to coagulate and stick, the soap likewise, also acting as a foaming agent meaning you get a slightly better coverage. Otherwise the bi-carb/water on its will quickly run straight off, and the benefits lost.

It is known that fungus prefers an acidic environment, alkalizing the blood and body at a cellular level helps ward off fungal conditions in humans, hence the alkalizing effect of the baking soda is thought to be responsible for its effectiveness against frangipani rust.

You can pick up 500g – 1kg of baking soda for just a few bucks in the supermarket aisle where you find sugar, salt and spices, it is after all primarily a baking additive with many alternative uses. It’s also a fantastic cleaner for the kitchen and bathroom, it’s even in toothpaste! Put it in a hot detox bath, or even soak your hand in it to remove a troublesome splinter – try it, it’s amazing. And please note that baking powder is not the same thing as baking soda, otherwise you’ll be disappointed.

Epsom salts which have a high pH when dissolved in water may also be effective, the benefits within the garden of which could be the subject of an entirely separate article. Hopefully next time we discuss frangipani we can talk about the brighter side of things, such as grafting multiple plants together to produce a multicoloured plumeria – if you have the initiative give it a go the results are amazing. I have covered frangipani rust a few times in the past, read the links supplied for more detailed information.

Dealing with Frangipani Rust?


Dr. Kris

Garden Doctor


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