How low can they go? Some citrus trees can tolerate the rare occasions of low temperatures in Australia with little or no damage. Trees less than three years old should be covered when frost is expected. In frosty areas, always plant citrus trees in the spring.
• Cumquats are able to take -7°C.
• Mandarins, Meyer lemons, Seville oranges and calamondins tolerate up to -6°C.
• Sweet oranges accept -5°C.
• Lemons and grapefruit tolerate up to -3°C.
• Limes prefer no frosts, but can take -1°C.
Climate The only places to think twice about planting citrus are the country’s coldest districts. Citrus don’t like prolonged cold or repeated heavy frosts but (lucky for us) that happens hardly anywhere in Australia and certainly not in any of the mainland coastal capitals. (For a guide to cold tolerance, see box at left.)
Aspect Full sun, preferably sheltered. In very hot areas, afternoon shade helps.
Soil Average garden soil will suffice as long as it drains well and does not stay sodden after rain. The deeper, darker and better quality your soil, the stronger your trees will be.
Planting Anytime from now until the weather is consistently hot. The next best planting time is early autumn. Allow room for the canopy to spread (4–5m across).
Pots Suitable for all citrus trees. Start with a 40cm pot, then, if required for larger growing varieties, repot into a bigger container after about two years, and again two to three years later. Use top-quality potting mix and at each repotting, mix in a ration of long-term controlled-release fertiliser. Always ensure containers have adequate drain hole.
Water Young plants in the garden need watering twice a week. As they grow, water as the weather dictates. They like moisture at the roots so give a good, deep soaking when it’s hot. Water potted plants more frequently during summer and less when it’s cooler. A rule of (green) thumb is to poke your finger into the soil down to the second joint – if it feels moist, don’t water.
Fertiliser Feed garden plants after picking all the fruit and again about six weeks before the tree flowers. Use a granular citrus food, watering in well after each application. Feed potted plants monthly with a soluble fertiliser. If the leaves start to go yellow, water less and fertilise more.
When to expect fruit!
There’s a different variety of citrus ready to pick every month of the year.
• Navel oranges ripen between June and October, directly followed by Valencias until March.
• Mandarins ripen in autumn and winter – the earliest in April and the latest in August.
• Lemons are most abundant in winter, but can be picked from at least February to October.
•Tahitian limes ripen from October to March in northern Australia, December to March in the subtropics and April to July in the Sydney region. West Indian limes (best in Brisbane) ripen in summer and autumn.
• Grapefuit comes on in winter.
• Calamondins and cumquats ripen from May to September.
• Native finger limes are ready to pick in autumn.