LAWNS: Keep an eye on grass colour. It is still a little premature to apply fertiliser on all but the weakest lawns. When couch and kikuyu go a little yellow, probably towards the end of November, will be the optimum time to apply fertiliser so that the grass can survive the hotter weather in December and January. Be guided by the volume of clippings coming off each lawn. When they diminish will be the time to fertilise and also to raise the cutting height.
Many grasses that were literally growing out of their skins last month with a bit of rain and sunny days, have used up all their energy and depleted the food reserves stored in their roots, and are now thin and stringy. Definitely fertilise these as soon as you can, but make sure that they are being irrigated. The few light rains that we might expect between now and Christmas are not sufficient to keep the grass growing.
Citrus trees require comparatively large amounts of nitrogen, so fertilise with a complete mineral fertiliser with additional sulphate of ammonia so the total NPK is 10:4:6 plus the trace elements from mineral mixture. Apply 500g per year of tree age, but do not use more than 2.5 kg per tree.
Manganese, and zinc are important trace elements that are gradually converted into insoluble phosphates and oxides, locked into the soil and unavailable to the plants. Organic-only pellets or straight blood and bone only give lush, shiny leaves and do nothing for fruit set because they lack essential potassium and trace elements. ALMA No 4 fertiliser for lawns is ideal for use on citrus for it contains a useful trace element package – copper, iron, magnesium and manganese, with an NPK analysis of 15-.2-8.
Apricot Gummosis: This wood fungus disease is very common in SA. where it is mainly a disease of apricots, but it can also infect grapevines. In apricot trees it usually shows up in late spring when the tree is loaded with fruit, then suddenly within a week, a huge branch wilts and dies.
To treat this problem, you need to remove the whole of the branch. The point of infection will often be oozing gum. The final cut should be free of dark staining in the wood. Any sign of staining indicates that the disease has moved lower into the tree. Immediately paint the cut with a couple of coats of tree paint containing a fungicide, or mix a teaspoon of copper, mancozeb or chlorothalonil fungicide in 100 ml of water based house paint. Dispose of all infected wood.
Black spot may be appearing on roses. A 10% solution of milk and water sprayed over the foliage helps to control this disease.
Dead branches on Cypress and other conifers that get blown out by winds are invariably attacked by cypress bark weevil at this time of the year. The pest is a 6mm weevil that lays its eggs in the bark. Larvae tunnel through the centre of stems, disrupting sap flow.
Except for general cultural practices that improve tree vigour, little can be done to control most bark beetles beneath bark once trees have been attacked. Prune and dispose of bark-beetle-infested limbs. Promptly remove the entire tree if its main trunk is extensively attacked by bark beetles. Unless trees are monitored regularly so that borer attack can be detected early, any spraying is likely to be too late and ineffective. Sprays will not kill larvae tunneling beneath the bark and must be directed at the adults as they bore into the trunk to lay eggs.
Excessive mulching around trees or shrubs can kill with kindness. There are many negative results from over-mulching around trees. This is especially true if the mulch material is piled around the trunk area – a practice, that unfortunately, is becoming more and more common. Normally, trees should be mulched to a depth of 10 centimetres.
One of the cruellest afflictions at this time of the year has to be hayfever. The wind pollinating plants are the greatest villains: Pines, including Cupressus, the ‘native pine’ Callitris, silver birch, Ash, Plane, Elm and Privet produce huge volumes of pollen. And of course Wattles, Melaleucas Callistemon and Sheoak are flowering as well. Then there are the grasses. Salvation Jane is in full flower. Couch grass if left for two weeks without cutting will flower in summer. Rye grass, wild oats and Barley grass are almost past their seasonal peak but their pollen is so light that it can be carried by the wind for hundreds of kilometres. There are so many plants that are copious pollen producers that cutting down the obvious tree just may not be the cause of your hayfever all.