Rose bushes may struggle to establish if they are planted poorly, given little in the way of aftercare or planted where a rose has been planted before. Even if properly planted, rose bushes are susceptible to a few pests and diseases, but these issues can be fixed with proper care and attention.
Rose Replant Disease
Rose bushes may suffer from a sickness known as replant disease. Replant disease occurs when a plant is replaced with the same type in the same position. For most plants this doesn’t cause an issue but for some, including roses, the new plant will fail to thrive or grow well.
This doesn’t just occur in areas where the previous plant was well established. The roots of the previous plant only need to have been in the soil for a few months for this to occur. In severe cases replant disease can cause the new plant to die and the fine roots might turn rotten or grow poorly.
However, this issue can be fixed fairly easily by lifting the plant, shaking off all the soil and replanting it in a different site. The plant often recovers if these steps are taken.
Rose Black Spot
One other problem that these plants face is rose black spot. This is the most serious rose disease. It is caused by the fungus Diplocarpon rosae which infects the leaves and greatly reduces plant vigour.
Large purple or black patches appear on the leaves in spring and they turn yellow and drop. Small black lesions might also appear on young stems. Plants that are badly affected might lose all their leaves.
To fix this issue make sure to collect and destroy any of the fallen leaves in autumn and prune out the lesions in spring. This will help to delay the onset of the disease.
Use fungicides such as tebuconazole (Bayer Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Bayer Fungus Fighter Plus), and triticonazole (Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun) to help keep in control of the issue.