Your garden: July 1

Vegetables

Crop rotation may sound overly scientific for the ordinary gardener but it is an important way of getting the most from the vegetable garden and, at the same time, minimising the risk of diseases such as club root in cabbages or basal rot (caused by Fusarium oxysporum) in onions, garlic and leeks.

Designed so crops take different minerals from the soil each year, good rotation will take account of chemical and physical differences between plants. The basic rule is never to grow plants from the same family or type in the same spot two years in a row.

Leaving aside perennial vegetables such as rhubarb, globe artichokes and asparagus which stay in the same plot, divide your garden into three areas.

Make a list of what crops can be grouped: potatoes, celery, leeks, carrots, parsnips and beetroot in one group; peas, beans (all types), onions and spinach in the second; and brassicas (including brussels sprouts, cabbages, broccoli, cauliflowers and kohl rabi) in the third. Grow them by groups this coming season.

In the second season, grow tap-rooted plants (group one) in plot three, the ground previously used for brassicas. Put potatoes and the onion family into area one and brassicas in the remaining part of the garden. Year three sees brassicas in plot one, tap-rooted plants in bed two and onions as well as potatoes in the third section.

Continue this practice in subsequent years. A garden diary may make it easier to remember the movements or draw a computer-generated plan and mark what was sown or planted where, with planting or sowing dates.

Flowers

Rose-planting time has arrived and nurseries soon will be full of this most popular shrub.

In a perfect world, the gardener would have deeply dug the spot for new roses some weeks ago to give the ground time to settle naturally before planting. In reality, this may not be done until the roses have been bought, so put the bare-rooted roses in a corner of the vegetable garden until the site is ready.

Dig out holes for roses 1m apart and about 30cm deep.

The depth depends on the soil type. Shallower is best in heavy soil but deeper holes are recommended in light, sandy soils that become hot and dry during summer.

The holes should be wide enough to allow the roots to lie without obstruction. Help them rest slightly downwards by forming a slight mound in the centre of the hole. Cover with good soil and apply commercial rose fertiliser.

Fruit

Winter spraying of apples and pears with a winter oil spray will help control woolly aphids, scale insects and red spider. If you prefer not to spray, attracting waxeyes to the garden by putting a shallow container of sugar water on or near fruit trees will encourage them to clean up bugs.

Good garden hygiene is also important in preventing or controlling disease. Any fruit remaining on trees or on the ground through the winter may be a source of primary infection and should be removed.

Apple trees infested with woolly aphids and pears with scale insects or red spider should be given a winter oil spray.

Thoroughly cover all parts of the tree.