Ludwig’s rose corner
Rose guru Ludwig Taschner offers expert advice…
Q: Even though I spray my ‘Black Tea’ roses, they still seem to be affected by black spot after the rains. Do you have any advice?
There could be several reasons for this. Roses that are undernourished (with light, greenish-yellow leaves) are susceptible to black spot, despite spraying. Apply Vigorosa around the plants, water in well and within a week, the light green leaves, which are a clear indication of nitrogen deficiency, should turn green and increase in size. It could also be that the leaves were already infected when you sprayed, so the fungicide would not have had any effect. During extended rainy periods, the spray is washed off by another shower. Use Chronos (with a sticker like Picanta); it penetrates the upper layer of the leaf and won’t be washed off. It also has a curative action on roses that are already infected.
Q: The leaves of my ‘Fragonard’ rose have a lacy appearance; what causes this?
The leaves are being eaten by the chafer beetle, also known as the Christmas beetle. It is active at night when it eats the leaves, leaving them with a lacy appearance. When you notice the beetles, spray with Ludwig’s Insect Spray or Rose Protector, or dust the leaves with Karbadust. To make a trap, set up a light with a bucket of water and oil underneath or use a blue insect light.