Over the last month, rose blooms have risen to their most radiant, but gardeners beware—the threat of black spot looms, ready to mar these floral beauties. This most perilous of rose diseases thrives amidst the hot, damp climate of summer, making short work of petals and leaves, spreading through water and stubbornly clinging to the soil.
The telltale signs of black spot are unmistakable – circular black marks on the leaf’s surface leading to wilted plants and withered blossoms if left unchecked. Left to fester, black spot can rob roses of their strength and splendour, an expert from Gardening Calendar advises. They said: “Remember, for all types of fungal conditions, the fact is fungus spores are always present.
“Fungi simply stay in a dormant state when conditions are less than ideal.
“This is why it’s very important to create an environment that is conducive to good rose growth and hostile to the growth of fungus.”
How to stop black spot disease this summer
Check and spray your roses
Combatting early black spot with regular checks and sprays is simple yet effective, with baking soda hailed as a particularly useful ally.
This alkaline warrior disrupts fungal spores in their infancy, dampening their infectious potential.
The experts said: “Make a baking soda solution by dissolving a teaspoon of natural baking soda in a quart of warm water.
“You can also add a teaspoon of dish soap. Spray your plants and leaves thoroughly to prevent black fungal disease and also powdery mildew.”
Employing baking soda is an effective, gentle method to tackle the early signs of black spot to ensure your roses remain lustrous throughout the summer. Some other gardeners have also found coffee can help.
And others say to have bigger, long-lasting blooms, you need to mulch, especially in hot weather.
Creating adequate space for your roses is crucial
Due to Britain’s frequent rainfall, limited air circulation among plants can lead to moisture accumulation.
Excess moisture and stagnant water are breeding grounds for black spot and other maladies, so it’s vital to inspect your rose bushes weekly, pruning overly dense stems to avoid congestion.
The gardening expert said: “Be sure to prune your roses regularly so that there is enough space between the canes for good air circulation. If your roses become too dense, they will be susceptible to black spot disease.”
Ensure you’re watering your roses correctly each week
To stave off black spot, it’s paramount you avoid getting water on the plant’s stems, leaves, and flowers; instead, aim to deeply irrigate the base soil around them once a week.
The expert said: “When you use this method of watering, you avoid splashing fungal spores up from the ground. By keeping the leaves and flowers dry, you avoid creating a habitat for fungus.”
Maintain a tidy garden
The specialist advised: “When you leave them lying around, any spores that may be on the leaves will reproduce rapidly and can be blown about easily.”
Excess moisture can accumulate in decaying plant material, attracting pests, so it’s essential to collect it and dispose of it in the rubbish bin, rather than the compost bin, to maintain a healthy garden.