Citrus in all its varieties is presently one of the most popular categories of fruit trees available in nurseries. This is mainly due to the work that has been done in recent times to provide dwarf growing forms that are more suitable to pot culture or for our ever-decreasing house block sizes.
In growing citrus a great deal of importance is placed on the location where you live as many are not suited, for instance, to heavy frosts or cold southerly winds.
Optimal temperatures for growing citrus are between 25 and 30 degrees Celsius. When temperatures get above 38 degrees, growth is inhibited although the plant will survive up to 50 degrees. Oranges and lemons are more suited to colder parts of our area although some frost protection is required in very cold locations. Limes and cumquats require a really warm, frost-protected site.
Satsuma mandarin, Meyer lemon and sour orange are more tolerant of cold and can be grown in a more exposed position. Locations along the coast like Narooma and Bermagui are suited to all citrus as long as they have protection from the cold south winds.
When selecting the site for your tree ensure that it has as much as six hours a day direct sun and a well-drained, compost-enriched soil. The site should have as much wind protection as possible but particularly from the south.
Dig a wide hole, but not massively deep, and add a commercial planting compost to your soil. If you have made your own compost ensure that it has broken down sufficiently to mix with your soil. Don’t completely change your soil when planting, but improve the soil you have.
Once you have placed the plant in the hole, check to make sure when you backfill the hole that soil does not come up above the graft—basically just enough soil to cover where the soil came up to in the pot.
If you don’t have sufficient room in the garden and you still want a citrus then try one of the dwarf forms. Mandarins, oranges, lemons and limes come in the dwarf form with at least two varieties available for each.
Citrus do very well in pots, particularly the dwarf forms, but pot culture of citrus is a bit different to growing plants in the ground for several reasons. Planting in pots requires a reasonable size pot so sufficient potting mix can be added. The larger the pot the more soil, to provide a greater water- and nutrient-holding capability. The smaller the pot the quicker the plant dries out and this leads to an unthrifty tree. Nutrient leaches out more quickly so it’s important to feed potted plants more regularly.
From my experience fertilising of citrus should take place in spring and summer with the addition of chook manure and a side application of fertiliser in autumn.
Citrus are gross nitrogen feeders so a specially formulated citrus fertiliser is most desirable. Apply at the drip line of the plant and water in well.
When fertilising potted citrus use a water soluble form so root burn is alleviated. A side application of fish- or seaweed-based fertiliser on a regular basis outside the regular fertilising program will also benefit the plant.
Citrus trees have several pest problems including sap-sucking pests like shield bugs, leaf miner and scale, with several fungal problems including black spot, Septoria spot and citrus blast. Ask your local nursery person for control measures to combat these problems; there are both chemical and organic forms of control for all these pests.
Call in and ask your nursery person what is the go with these great plants and find out that now is the time to plant.