ACTIONPLAN

NIGEL COLBORN’S ESSENTIAL JOBS FOR YOUR GARDEN THIS WEEK

You know summer has come when roses are in full bloom — and this year, they are bigger and better than ever. But if you want yours to thrive all summer, give them a health check. Begin by looking for pests. Aphids (greenfly) are especially bad this year, and affect both climbing and bush varieties. Dense colonies gather at the ends of young shoots and on maturing flower buds.

If you grow only a few roses, examine all shoots and bud clusters. Wherever you spot an aphid colony, gently rub the insects out.

Natural predators, such as ladybirds, lacewings and hoverfly larvae, will also turn up and help to control numbers. If you grow lots of roses, spraying is likely to be necessary. Contact sprays containing natural pyrethrum or fatty acids can be effective and are approved for organic gardening. The spray must land on the pest to work properly, however.

Among chemical controls, deltamethrin (as in Bayer ultimate Fruit and Vegetable Bug Killer) or cypermethrin (Py Bug Killer) will also kill pests on contact.

Fungal diseases cause trouble with roses, too. Mildew, black spot and rust are widespread among nonresistant rose varieties.

Combined products such as Scotts Rose Clear ultra, or Bayer Multirose 2 control both pests and diseases in roses.

If you dislike spraying, grow individual roses in isolation and choose varieties with resistance.