Question: Why are my rose bush leaves turning yellow all of a sudden?
Hardiness Zone: 7a
Ann from MA
Answer: Hi Ann,
I agree with Elaine (in the feedback forum below). It sounds like your roses have experienced a fungal disease called Black Spot. Black Spot is a serious, but controllable, disease commonly seen in floribundas, hybrid teas, and grandifloras. For whatever reason, shrub roses don't seem to be affected by it as much.
Black Spot is caused by fungal spores and typically occurs during warm, moist conditions when rainwater splashes the spores up onto the foliage from the ground. Black spots and yellow patches appear on the leaves, which then shrivel up and fall off. If left untreated, a rose bush can quickly lose all of its leaves.
To treat roses with Black Spot, remove any visibly infected leaves and throw them into the garbage. Composting is not recommended, as fungal spores can remain dormant for long periods. Fallen leaves lying under the plant should also be cleaned up and disposed of in the same way. To prevent Black Spot from spreading to more leaves, dissolve 1 teaspoon of baking soda in 1 quart of water and spray the infected plants thoroughly. Severe infections can also be controlled with sulfur, which is readily available at garden centers.
You can't control the rain, but you can help control the spread of Black Spot by mulching around your roses to help prevent water from splashing the plants. Water your roses as early as possible in the day so leaves have time to dry, or avoid wetting the foliage altogether by watering from below.
Good luck!
Ellen
About The Author: Ellen Brown is an environmental writer and photographer and the owner of Sustainable Media, an environmental media company that specializes in helping businesses and organizations promote eco-friendly products and services. Contact her on the web at http://www.sustainable-media.com
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