Protecting Roses Against Black Spot
One of the most common questions we are asked here at Country Garden Roses is about Black Spot and what is the best way to remove and protect your roses from it.
Unfortunately, like all living things roses can suffer from pests and diseases. Season after season, the most common disease is Black Spot. Prevention is always better than cure, and with a little knowledge you should be able to keep your Roses clean, healthy and disease free.
What is Black Spot?
Black Spot, or Diplocarpon rosae is a Fungal Airborne disease. You can see a rose has black spot when there are dark brown or black spots on the leaves which then become yellow and will drop off.
Why do Roses get Black Spot?
As black spot is a fungal disease, warm, damp conditions, especially warm, wet summers favour germination and growth. When roses are planted too close together and there is not enough space for fresh air to circulate.
Which roses are most susceptible?
Generally, hybrid teas, grandifloras and miniature roses are considered more susceptible to this fungal disease. Floribunda roses, shrub roses and newer varieties of the climbers are considered more resistant, however all roses can easily be infected if not sufficiently protected. The only types of roses that are considered to be near-immune are the Rugosa Roses.
How to treat Black spot?
If you have already had a bad case of black spot, remove all the infected leaves from the plant itself and from the ground around the rose. Burn any of the diseased leaves to avoid any contamination.
Spray your roses once a week for a few weeks with Systhane or Rose Clear which will soon eradicate the problem.
How to protect your roses against Black Spot
Watering and Feeding - Ensure that your roses are all planted in appropriate conditions and are fed and watered sufficiently. Roses lacking in water or nutrients are more prone to catching diseases such as black spot.
Spraying - systematically spraying your roses with folia feed every two to three weeks should start as soon as leaves appear in Spring and will ensure that the roses leaves grow stronger and more resistant to disease. Use one brand twice, and then change to another brand twice, alternating throughout the season, until the end of August. Two Folia feeds we recommend are Uncle Tom’s Rose Tonic alternated with Plant Magic, both of which are available in our shop. Spraying with a fungal spray such as Rose Clear every 21-28 days from the beginning of the season until the roses become dormant in late September/ October also works as a preventative measure and should protect your rose from the majority of fungal diseases and pests, especially black spot.
Mulching - Mulching ensures that the soil is kept moist; weeds are kept to a minimum and disease such as black spot are suppressed. Use organic matter such as well rotted farmyard or horse manure which has been matured for at least 2/3 years in a good layer around the rose, keeping 2/3 inches away from the stems, to prevent spores re infecting after falling from the rose.