Black spot is a common disease of roses, and is especially prevalent in rainy and humid climates.
You may be putting on your nose to the rose and enjoying your favorite perfume when you notice some unsightly discoloration and yellowing on healthy bushes. The first thing to realize is that black spots are almost everywhere, and there is no reason to panic.
Black Sopt
Black spot is the most common fungal disease for rose gardeners worldwide. While this may sound scary, it is not a death sentence for your rose. There is no cure for dark spots, but you can take steps to minimize the damage and prevent future problems.
Let’s dive into everything you need to know about black spot and how to prevent this fungus from taking over your rose garden!
The disease spreads during the growing season, but also thrives when infected leaves and canes are left over winter, reinfecting plants in spring. This eyesore is primarily a cosmetic problem, but when left untreated, it can weaken your rose and cause it to lose its leaves.
While this may seem risky, it’s best to assess the overall health of your rose and take a common-sense approach to treatment. Let’s review the main symptoms and what to do if you notice this pesky fungus appearing on your roses.
This fungal disease is easy to recognize. It first appears as black, brown and sometimes purple spots on the lower leaves of the plant, gradually moving upwards. Often, yellow areas form around the spots before the leaves fall from the plant. Sometimes, you will also see brown or rusty spots on fresh canes.
Symptoms
- Irregular brown, black, or purple spots on leaves.
- Yellowing of spotted leaves.
- Leaf loss.
- Canes with a brown or rust-colored rash.
Pro Tip: Rust-colored scabs look similar to rose canker, another common fungal infection of roses. The disease usually appears as a surface discoloration, while pus comes from bite wounds and looks like a sore on a stick.
Reasons
The most common causes are lack of proper air circulation, wet, humid conditions, and lack of sanitation. However, remember that most gardeners, even experts, sometimes see this fungal disease pop up in their gardens.
Prevention
There is no way to completely eradicate this fungal disease. Remember that this is mainly cosmetic, and stay calm. However, there are some important ways you can reduce the likelihood of it becoming a major problem in your garden.
Plant disease-resistant varieties
When choosing roses to grow in your garden, choosing disease-resistant varieties is the most important step in reducing the chances of future fights with fungus.If you love a particular type of rose, such as hybrid tea, which is more susceptible to black spot, choose the rose with the highest health rating you can find.
Generally yellow roses are more sensitive. If yellow is your favorite color, avoid hybrid teas and choose a hardy rose variety so that sunny-colored roses have the best chance of success in your garden.
Watering
Water your roses at the base of each plant to prevent soggy plants. If possible, water your roses in the morning to give them enough time to dry out during the day.
A drip irrigation system is ideal, but you can also leave your hose at the base of the shrub, giving it a good soak (2-4 gallons) once a week. If you have particularly hot conditions or a newly planted rose, increase the amount twice a week or more.
Proper air circulation
Make sure your roses are properly spaced, leaving 3-4 feet between each plant. When pruning in early spring, maintain a bouquet shape with open air flow in the center of the rose and strong, sturdy canes around the outside. This will reduce the chances of wet, overcrowded plants.
If your infected roses are in the shade, consider moving them to a sunny location where dry conditions will reduce the germination of fungal spores. Some varieties can tolerate partial shade, but most roses do best in 6 to 8 hours of direct sunlight per day.
Cleaning of rose garden
After removal, clean up any diseased plants and remove them completely from your garden. Always disinfect your shears with a quick dip or spray of rubbing alcohol between each plant to prevent disease from spreading throughout your garden.
Treatment
If black spot has already appeared in your garden, don’t panic. Remember that almost all rose gardeners suffer from this disease from time to time!
Over-reacting, over-pruning, and spraying your roses with synthetic chemicals can cause unnecessary damage. There is no cure, only prevention and ways to stop the spread. Here are some steps you can take to reduce the problem before it gets worse.
Remove affected plants
First, put down the pruners! Use your hands to gently push down and back to remove the colored leaves. They should come easily. Bag them up and get them out of your yard. If you notice spots on your canes, assess the overall health of your roses before removing them. For small roses that are just starting out, you may want to see if the rose can tolerate a little black spot rather than removing all of its new growth.
If you have a sturdy, old rose with lots of healthy canes, go ahead and cut out the infected canes with your shears along with the diseased leaves.
Organic treatment
Often, removing affected plants, providing adequate air flow, and keeping plants away from water are sufficient to manage black spot. But what if you live in a particularly rainy, humid climate?
You can try some tried and true organic solutions used by expert gardeners. Caution: Even organic solvents affect pollinators in the garden. Please use sparingly and only in the evening to avoid killing beneficial insects.
Synthetic treatment
If you’ve tried everything listed and black spot is still present in your garden, weigh your options. A small amount of this disease can be tolerated. However, if your roses are losing all their leaves due to disease and the plants are becoming weak, you may want to consider more drastic measures. Before introducing harmful chemicals into your garden, think about:
Hard Pruning: Remove remaining foliage, and prune until you see a green, healthy cane. Clean thoroughly, and your roses will produce healthy new growth next season.
Pickomg a new variety: If you’ve planted particularly sensitive varieties, consider whether they’re worth keeping. In their place are reliable resistant bloomers that you can enjoy without constant interference.
If you want to use a synthetic chemical solution to deal with dark spots, wear gloves, eye protection, and a mask to protect yourself. Plant in the evening to avoid contact with pollinators as much as possible. Be careful to follow instructions to keep children and pets out of your garden until the solution dries.
