Winter is the time citrus trees come into their own. Not only are their fruits ripening into golden and orange orbs, but being vitamin C rich, they are also the perfect treatment for colds and flues and staving off infections. In pots or in the ground, who can resist a plant that rewards you so reliability with fruit?
To get the best from your citrus, and help them help you, it makes sense to keep them pest and disease free. Winter is a great time to break the cycles of many pesky problems like citrus gall wasp, fruit fly and scale.
- Citrus gall wasp causes swellings in the stems that lead to reduced harvest and lack of vigour. The best treatment is to prune these off now before the wasp emerges in spring. Make sure you bag or burn the stems, rather than compost them, to break their life cycle.
- Fruit fly can over winter in winter ripening fruits like loquats and citrus. Treat with Yates Nature’s Way Fruit Fly Control by spraying the lower foliage and making a band around the trunk that will kill both Queensland and Mediterranean Fruit fly with a naturally occurring soil bacteria.
- Scale insects can also be a problem for citrus, and the cool weather of winter allows you to treat your plants with Lime Sulphur. This is great for getting rid of White Louse Scale, which are the small white flecks you see on your plants’ trunks. You can also treat the foliage of your trees with white oil in winter, which will kill the soft scales on your plants like brown scale.
Prune, Feed and Mulch
- Remove and shoots from below the graft and remove and low lying branches that reduce air flow.
- If you have a mature tree and want to reduce its size, winter is the perfect time to give it a hard prune…but you’ll probably miss out on the fruit!
- Avoid feeding during winter as it can force new growth, which is susceptible to the cold and will not be helpful for the developing fruit. Save your fertiliser for spring when your tree will be hungry and ready to flower.
- Remove your old mulch and replace it with fresh sugar cane mulch. This will help remove and fungal spores and insects, as well as supplying gentle amounts of nitrogen - be extra cautious not to pile mulch around the trunk, as this can cause collar rot.
Other things to note
Citrus don’t like severe cold, which is why in Europe they are grown in pots and brought indoors for the winter. If you’re in a cold area, you can cover them at night with hessian or an old sheet when the forecast is for very cold nights. The cold is good for helping to ‘sweeten’ your fruit, and many people wait for a frost before picking their oranges so that they become super sweet. Don’t wait too long though – fruit left on trees can attract rats, and oranges may regreen as a protection from the sun.
By: Meredith Kirton