The center of the flower needs a light wash of Lemon-Yellow hue mixed with Sap Green to imitate the look of fresh petals. I’ll add the same colour in few other places to make my artwork more cohesive. To anchor the flower and paint the stem, I use a saturated wash of Dioxazine Purple with Sap Green.
Rose problems: frequently asked questions
Roses seem to suffer from more than their fair share of problems. It is probably partly because this much-loved plant is so widely grown, and often in formal rose borders or gardens so that any problems are soon noticed. That said, some of the older cultivars in particular can be very prone to foliar diseases.
Rose problems: frequently asked questions
Quick facts
- Aphids
- Rose black spot
- Rose powdery mildew
- Rose dieback
- Rose leaf-rolling sawfly
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Root decay in roses can be the result of an attack by a root disease. Honey fungus is quite common on soil-grown roses and plants grown in soil or containers can sometimes be affected by Phytophthora root rot. Roses are suitable for growing in clay soils, but prolonged waterlogging can result in root rotting. Drainage problems in containers can also lead to waterlogging and root death. Root death in container-grown plants can sometimes be the result of hard frosts – the roots can be given some protection by wrapping the container with bubble wrap.
Branch dieback on roses is very common, and it is unusual to see a rose bed without at least a small amount of die-back. There are a number of different causes. Die-back can be a symptom of the root problems described above, as the plant struggles to take up water through its poorly-functioning root system. Sometimes the die-back is the result of a fungal pathogen colonising the branches themselves. The fungi found most commonly are Paraconiothyrium fuckelii (a cause of rose canker) and Botrytis cinerea (grey mould). These fungi are quick to colonise the branches of roses that lack vigour (due to pests, foliar diseases, nutrient deficiencies, etc.), or branches that have suffered physical damage (e.g. from frost or poor pruning technique). Many of these factors can cause dieback in their own right, but colonisation of affected branches by the die-back pathogens can greatly increase the severity of the problem.
The stems and branches of my rose are covered in small, brown, limpet-like structures. What are they?
These are scale insects. The species found most commonly on roses is brown scale. A flat, circular whitish scale known as scurfy rose scale can also encrust the stems
The most likely cause of this symptom is a bacterial disease called crown gall. The roots can also be affected.
Stage 1
I start by making a light sketch using a hard graphite pencil (2H). The goal here is to draw in a loose way, mimicking the natural movement and shapes of the flowers. Once I’m happy with the general appearance, I’ll use a kneaded eraser to lighten my marks as much as possible.
Stage 2
Then I’ll move onto painting the shadows with Dioxazine Purple. In areas where the shadow is strongest, I’ll mix Dioxazine Purple with Ultramarine to add depth. I use a round brush at this stage (Cotman size 6). The belly of the brush covers large areas, while the tip is good for precision.
Stage 3
It’s time to add some colour! Permanent Rose is a beautiful pink shade to add as a second layer on the flower. I’ll add dimension by colouring one side of each petal with a double layer so it appears darker. To create highlights, I’ll use a clean damp brush to remove some pigment from the paper.
