These highly ornamental fruit trees produce bright orange fruit in winter, and scented white flowers in spring. They make good-looking pot plants on a balcony, patio or couryard. Here are some tips for keeping yours thriving and producing.
Any citrus grown in pots need extra attention to thrive, including regular fertiliser, trace elements and water. These tips apply to all citrus, as well as potted camellias, Japanese maples and gardenias.
Choose a container about 45cm wide. It can be plastic, terracotta, cement or fibreglass, but must have adequate drainage. Position it in a spot that receives at least six hours of sunshine each day.
In wet-winter climates, elevate the pot on ‘feet’ to allow excess water to get away. Use a premium potting mix with five red ticks on the bag. Once a year, use a bulb planter to take out about four lots of the spent mix. Throw this onto a garden bed and replace the holes in the pot with fresh mix. Add six-month controlled-release fertiliser twice yearly. Water fortnightly with a fertiliser that’s a mix of fish emulsion, liquid seaweed and liquid compost, as frequent watering flushes nutrients from the pots.
Mulch with 3cm of compost twice a year, and cover this with lupin mulch or pea straw. These conserve moisture, protect the plant’s surface roots and provide nutrients as they decompose.
Once a year, spray the foliage with complete trace elements, and repeat this if there are signs of nutrient deficiency, such as discoloured, yellow or curled leaves. Water your potted cumquat three or more times a week in summer, when pots dry out quickly, but only once a week in winter, if you receive winter rain. Before watering, check soil moisture by inserting your finger about 3cm into the mix. The soil should dry out between waterings, as citrus hate wet feet.
For more information on growing citrus, especially unusual ones such as citron and pomelo, check out the August 2019 issue of ABC Gardening Australia magazine.