Time for the garden’s winter haircut and pest clean up!

From now onwards the garden looks at its worst, until everything starts to sprout in spring.

The upside is that this is the best time to assess the garden. Winter has stripped the garden of much of its foliage, and it is easier to see what needs to be cut back, neatened or moved.

What to prune in July?

Besides the roses, July is the month to prune and shape summer flowering shrubs and creepers that flower from October onwards.

From the end of July into August vigorous shrubs such as Plumbago, Abelia, Duranta, Pyracantha, poinsettia, Pentas and Solanum can be cut back by half or even two thirds to prevent them from getting huge and woody in the centre. Try to maintain a nice, rounded shape.

Hard pruning (almost to the ground) rejuvenates shrubs such as plectranthus, wild dagga (Leonotis)  ribbon bush (Hypoestes aristata) and vigorous creepers. .

Renewing the soil

But pruning is only half the story. For pruned plants to bounce back in spring they need fresh nutrients and loose, aerated soil for good drainage and root development.

Digging in compost or manure, topped off with an application of fertiliser will ensure the best possible start for them in spring. Water well after fertilising.

Opt for a fertiliser that contains both macro and micronutrients like Ludwig’s Vigorosa 5:1:5 (25) that also contains humic acids which play a very important role in the improvement of soil structure and water retention capacity. The organic component in the fertilizer contains up to 20% carbon which is also necessary for soil fertility.

Be careful not to prune shrubs that flower in spring, such as azaleas, camellias, magnolias, May bush (Spirea), and Mackaya bella. Wait until after they have flowered. However, fertilising them once a month from now until August will encourage a good show of spring flowers,

Because Vigorosa is effective for all soil types, from alkaline to more acidic, it can be used on these acid loving plants, as well as hydrangeas, because it does not contain agricultural lime.

July is also the month for pruning peach trees, nectarines, apricots, plums, apples, pears and cherries. Once the framework of the fruit tree has been formed (during the first three years of growth) the trees are pruned for better fruit production.

Eradicating winter pests

Pruning can reveal problems like infestations of scale or mealy bug. Scale insects have a hard body that is impervious to most insecticides. They suck the sap out of the stems and can kill a plant or stunt its growth.

Start by rubbing off as much of the scale as possible with a soft nail brush and follow this up  with a drenching of the stems with Ludwig’s Insect Spray at twice the recommended strength. Margaret Roberts Organic Insecticide could also be used. The reason why both are effective is that they contain canola oil which smothers the remaining scale.

Ludwig’s Insect spray will also kill off over wintering stages of insects like red spider mite.

Pests may not be as active in winter, but that doesn’t mean they are absent. Aphids, cabbage caterpillars, semi-loopers and amaryllis worms are prime offenders.

In the veggie garden the aphids and caterpillars target the brassicas, especially developing cabbage heads and the underside of kale leaves.

The most destructive pest by far is the amaryllis borer, a black and yellow banded caterpillar, that damages the leaves and bulbs of amaryllis, clivia and other lilies. It burrows into the bulbs and kills the plant. The larvae enter and feed on the leaves, make visible tunnels on the leaves.

 The solution for these pests is Margaret Roberts Biological Insecticide, that is a water dispersible granular microbial insecticide containing Bacillus thuringiensis var. kurstaki, for the control of caterpillar species.

When young active feeding larvae eat the treated foliage, they stop feeding within a day or so and die within three to four days. . This may take longer in cold conditions.

Spray the leaves in late afternoon or early evening when the caterpillars are feeding. It is not necessary to spray the larvae. Spray every seven to 14 days to break the life cycle of the larvae and prevent them from maturing.

For more information visit www.kirchhoffs.co.za

The Citizen