If you're a gardener or just love flowers, then chances are you may be familiar with Gardenias. Gardenias are a popular flowering plant that produce sweet-smelling blooms with glossy green leaves. However, these beautiful plants can be susceptible to a disease called Gardenia Canker, which can cause significant damage if left untreated. Today we’ll discuss what Gardenia Canker is, how it spreads, and the methods available to prevent its spread. Keep in mind, this disease is not curable currently.
(Photo: Steve Harris, 2023)
Gardenia Canker is a fungal disease that affects Gardenias. It's caused by the fungus, Phomopsis Gardeniae, and can cause cankers on the plant's stems and trunk and lead to premature flower and bud death. These cankers are usually small, sunken areas on the plant that are discolored and mat sometimes ooze a sticky substance. In severe cases, Gardenia Canker can cause defoliation and even death of the plant. Initial symptoms will be splotchy green and yellow foliage and swelling of tissue near the infection source. You may notice that buds die prematurely, and leaves will eventually brown and die as well.
(Photo: Steve Harris, 2023)
The fungus that causes Gardenia Canker can spread easily from infected plant material and it survives winters by residing in the cankers it produces. It can also spread through water, especially overhead irrigation, and wind, making it difficult to control once it has infected a plant. To prevent the spread of Gardenia Canker, it's essential to identify infected plants early and take steps to stop its spread.
One effective method of preventing the spread of Gardenia Canker is by sealing cankers. To do this, you need to prune out the infected areas of the plant and seal the wounds with a fungicidal sealant. This will help prevent the fungus from spreading to other areas of the plant or to nearby plants. The fungicidal sealant should be applied directly after pruning, following the manufacturer's instructions. For less chemical options, a mixture of Sulfur and Neem may help reduce some infections, but a systemic is typically the best route.
As mentioned, one method of controlling Gardenia Canker is by using systemic fungicides. Systemic fungicides are chemicals that are absorbed by the plant and move throughout the plant's tissue, providing protection from the fungus. These fungicides can be effective in suppressing symptoms of Gardenia Canker, but they're not a cure for the disease. It's important to follow the instructions on the fungicide label carefully to ensure safe and effective use.
Finally, it's essential to sterilize pruning tools and other gardening equipment to prevent the spread of Gardenia Canker. Sterilizing equipment helps to kill any spores that may be present and prevent them from spreading to other plants. To sterilize pruning tools, soak them in a solution of 70% rubbing alcohol or 10% bleach for 30 seconds to 1 minute, then rinse with water and allow them to air dry. For those comfortable with and able to do so safely, fire or a lighter can also be used to sterilize metal pruning tools.
I’ll wrap this up quick today, but, Gardenia Canker is a fungal disease that can cause significant damage to Gardenias if left untreated. Preventing the spread of Gardenia Canker can be done by sealing cankers, using systemic fungicides, and sterilizing pruning tools. Early detection and quick action are crucial in controlling Gardenia Canker, so be sure to keep an eye out for any signs of infection. For more information, consult with a local horticulturist or visit the websites of gardening organizations like the American Horticultural Society or the Royal Horticultural Society.
Sources:
- Clemson Cooperative Extension. (2021). Gardenia Diseases & Other Problems. https://hgic.clemson.edu/factsheet/gardenia-diseases-other-problems/
- University of Florida IFAS Extension. (2016). Gardenia Canker. https://edis.ifas.ufl.edu/pp313
- University of Georgia Cooperative Extension. (2022). Gardenia Diseases. https://extension.uga.edu/publications/detail.html?number=B1318