Are roses disease-prone? Or is it their culture?
July 3rd, 2026
In the week’s edition of ‘Ask Mike’, the You Bet Your Garden host addresses the common problem of yellow leaves on roses, and whether the likely cause is disease or something else entirely. Plus lots more topics when you tune into the entire show on audio at the You Bet Your Garden page at the Gardens Alive/Gurney’s website
Q. Someone in Hampton Tennessee whose name I have lost (probably for the better considering my answer) writes: “My friend told me about putting a table spoon of baking soda in a gallon of water on our roses for the leaves where they turn yellow. My husband faithfully did it last year and it really works.
A. Well, I can’t win here, so I’ll just get right to the point. A baking soda mix has long been used as a preventative against many of the diseases that roses can be prone to. The traditional recipe is to add a tablespoon of baking soda and a teaspoon of insecticidal soap, light horticultural oil or a natural dish soap to a gallon of CLEAN water (no city tap water), shake well and spray on your rose leaves (top and bottom) in the early morning—no other time of day—once a week.
However, yellow leaves are not on the list of diseases that baking soda and oil sprays are known to control. Sorry!
Yellowing where the veins remain green often points to chlorosis—indicating that your plants are suffering from a nutrient deficiency (generally magnesium or iron) or the soil pH is too high, (which alkaline baking soda would only make worse). It could also mean that the plants are water logged or possibly bone dry, but probably waterlogged. Or suffering from poor air circulation.
Other causes could involve wood mulch (the biggest disease carrier of any mulch and certain death to roses), chemical plant food, lack of adequate natural food, etc. Search ‘yellow leaves on roses’ at reliable sites (like State Extension websites’ NOT You Tubers or ‘influencers’ or people who are just guessing because they like to write stuff) and you will see a legion of possible causes for such discoloration.
Now: It is always better to prevent disease problems than try and cure them once they show up. I think it’s a good idea to give roses a baking soda and soap spray in the morning (and only in the morning) once a week, especially if the plants have had disease problems in the past. (But again, it won’t help with yellow leaves.)
If there is wood mulch anywhere near the plants, remove it and trash it; it is one of the worst things you can use in the garden—no mulch is better than wood mulch!
pH: If you want to do ‘the farmer’s test’, stuck your finger in the soil under the plant and taste a little bit. If it’s sweet, the soil is alkaline, which is bad for roses. Get rid of all mulch and debris under the plants and apply an inch or two of milled peat moss (which lowers pH and is also a great natural disease preventer) topped with an inch or two of compost (THE perfect plant food and also a great natural disease preventer).
And, as with tomatoes, never ever wet the leaves when you water; water at the base only. If the area is crowded, prune away other plants to improve air flow.
Oh, and if the soil tastes sour, that’s good. Sour indicates acidic soil, which roses crave. (If you want to use a ‘real’ soil test, you’re looking for a pH between 6.2 and 6.5—no higher than 6.8.)
No chemical plant food. It only creates problems. There are plenty of good organic and/or natural plant foods out there, including ones specifically for roses, which would add the nutrients you might be missing.
And remember the cardinal rule of correct gardening. As soon as you see a discolored leaf on any plant, remove it immediately and trash it. This will open up some airflow, reduce the possibility of disease spread, and most importantly, make your garden look better than your neighbors. And they’ll never know why.
