Toni Salter: Citrus

Just about every second property in Australia would have at least one citrus tree, albeit in a dubious state of vigour. What a great legacy our early European-Australians brought for us all to enjoy. Yet, their horticultural heritage has not necessarily been passed on down through the generations, with many of the “younger generation” pursuing academic and professional careers that their forefathers were not privileged to experience. Meanwhile, we’ve lost some of that family know-how when it comes to looking after the rogue citrus tree that we discover with joy when we move into our newly purchased first home.

“What the heck am I going to do with this thing?” we ask after we taste the shrivelled, bitter and tough results of our neglect.

Don’t be put off!!! And don’t be tempted to dig it up to make room for the planned pergola or “outdoor extension”.

Citrus are really very easy to maintain. And with a bit of work now you’ll have the best tasting oranges and lemons in the neighbourhood. Guaranteed! I remember transforming a 14 year old, fully neglected navel orange tree at the bottom of a garden in South Hurstville into the juiciest, sweetest orange I’ve ever tasted. It was so laden with oranges that neighbours all about were able to enjoy its fruit as a goodwill gesture from its owner.

So start by removing any left over fruit remaining on the tree now and throw out anything that’s fallen on the ground, it’ll only harbour fruit fly later in the season. Next get to work on the soil. Citrus love nitrogen, so plenty of nitrogen rich manure will give you lush dark green growth over the next couple of months. This’ll also help if your leaves have a yellowish tinge to them now. I use old chicken manure, compost and blood and bone to do the job perfectly. Be generous around the “drip line” (that’s where the edge of the canapy extends over the soil, new feeder root growth is established here) but don’t let any manure come in contact with the tree’s trunk. Give it a good soak with the hose before you lay a thick covering of mulch. Put about 7 cm of pea straw, lucerne and/or sugar cane mulch to do this. Grass clippings will do the job too, but you can’t lay them as thick. Heavy mulching keeps in the moisture and helps to break down the manure, giving the tree a continual supply of nutrients for months.

Wind will affect the fruitfulness of your citrus. So if you can protect it by growing a wind break around it then it will do much better. If it’s too exposed you may even have to consider digging it up, root ball intact and replant it in a more protected position. Good, deep and consistent watering throughout summer and autumn as fruit develops is vitally important. A long deep soak once a week is better than a light sprinkle every afternoon.

Now look at any pests. Scale is often a problem on citrus trees with little white or brown flecks stuck on the leaves and branches. These are the hard coatings that protect the sap-sucking insect underneath. You’ll probably also notice some grey or black powdery film all over the tree too. This is called “sooty mould” and is the mould that grows on the sticky honeydew secretions produced by the scale insects. Get rid of the scale and you’ll get rid of the sooty mould as well. So grab some white oil or pest oil and give the tree a good spray. Cover it to the point of dripping with oil, but don’t do it on a hot day or it may scorch the leaves. If rain comes then you’ll have to do it all over again. Once you notice the scale has gone, give the tree a spray with the hose to remove any remaining sooty mould.

Other bugs to beware of are “spined citrus bugs” and “stink bugs”. These bugs produce dry patches inside the fruit or a type of gum residue on the outside of the fruit. Treat these guys now at nymph stage with a splash of soapy water. Check especially on the underside of the leaves to catch all lurking predators.

Fruit that looks a bit like Uncle Fester and is covered in warts may have fungus called citrus scab. This affects the appearance more than the actual fruit. I usually ignore it and make sure there’s plenty of air circulating around the tree, thinning out the canapy to allow extra air flow. Keep the tree well fertilised and watered and it’ll generally grow out of it naturally. The same treatment applies for crown rot which displays itself with gumming around the base of the tree. Make sure the ground isn’t too moist and keep the mulch away from the trunk.

No more bitter lemons for you to suck on now!! Happy Gardening.

If you'd like to learn more, you can attend one of Veggie Lady's workshops.
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