PESTS AND PERILS

Roses are being bred to be more resistant to pests and diseases. But it pays for you to be alert to things that can go wrong.

APHIDS

These are sap-sucking insects found around tender buds, soft stems and new leaves, feeding on vital plant juices. They’re prolific breeders and can cover new growth in days, causing your bush to wilt and become deformed almost overnight. Remove them by hand or treat with a soap spray (don’t forget under the leaves). Spray again a few weeks later to remove any that have emerged from eggs and survived the spraying.

BLACK SPOT

The ugly splotches on leaves are caused by a fungus that strikes in warm, humid conditions. It can spread quickly and eventually the plant will lose all its leaves. Remove the infected leaves and dispose of them (but not in your compost). If it’s humid, ensure good airflow through the plant by pruning the centre of the bush. If using a fungicide, don’t spray in the heat of the day. If it’s a regular problem, spray lime sulphur on the plant and ground after your winter pruning.

POWDERY MILDEW

This is also a fungal disease occurring during still, humid conditions. It looks like white powder on leaves and flower heads, and will distort growth. Treat your bush as you would for black spot.

RUST

This is also a fungus and appears on leaves in spring as small orange or rust-coloured spots that grow bigger and darker as the infection advances. Leaves that are badly infected will fall from the bush, dramatically affecting its health. Like black spot and powdery mildew, it is caused by humidity or inadequate airflow through the bush. Treat as you would for black spot.

9 Make your garden breathtaking with this Rosa ‘Sensation’.

10 Add a touch of pink to your white roses. Try Rosa ‘Emily’.

11 You’ll get pots of gold when you bunch-cut yellow roses in various stages of blooming.

Pure white roses are rare. Most are creamy.