Growing Gardens

with Julia Hancock

Rejuvenating citrus trees

Whether you have had a bumper crop from your citrus trees this winter, or your trees have struggled to produce only a couple of fruits, it's time to tend to their needs.

Pruning citrus is not normally necessary but there are exceptions to every rule. Any branches that are crossing over have the potential to wear away at each other, causing wounds which are susceptible to attack from insects and diseases. These branches should be removed, as should any sappy new shoots growing inwards into the tree - these are called watershoots and are unproductive. Of course any diseased or dead wood should also be removed. Finally, look out for shoots that appear from below the graft (the knobbly bit at the base of the stem) as these will be coming from the Poncirus trifoliata rootstock, which has the ability to smother and kill its scion (the bit that's grafted onto it).

When you are pruning you may notice tiny white flecks on the trunk and branches. These minute scale have the ability to form large cracks in the outer layer of the trees wood, which weakens it to the extent that it will eventually die. There may also be another scale present - larger, brownish black lumps on the smaller branches and leaf petioles and undersides - which will probably be accompanied by sooty mould (a black film on the leaves) and ants running up and down the trunk. These problems can be solved with one product, PestOil, which should be diluted and applied as per the instructions on the bottle. Repeat sprayings may be necessary, but that's also a good thing at this time of the year as citrus leaf miner will be preparing to burrow into the new foliage as soon as it starts appearing in the next few weeks.

After pruning and spraying, soak the root zone well and apply some citrus fertiliser before watering again and mulching.

It's always great to have feedback from readers. I am indebted to John Moye for pointing out a couple of errors in my article on native orchids (Echo, August 19). I was wrong to suggest Dendrobium kingianum is found growing on trees; it should be grown on rocks in sheltered positions or in pots in the home garden. I should also have stressed that although dendrobiums are found in the bush, they should never be collected from the wild as they are protected under the National Parks and Wildlife Act. Orchids purchased from retailers should be sold with a National Parks and Wildlife label. My apologies to anyone who has been misled by my article.