A small tree (large shrub) to potentially 8 metres tall, spreading to about two metres wide. It has axillary spines and is quite thorny.
It is naturally found in the north-east corner of NSW (from Grafton, north to the border – close to the coast), extending north into Queensland to about Gympie.
It grows in dry and sub-tropical rainforest and can be prolific in disturbed regenerating areas.
Citrus spp. have simple or one-foliolate leaves (cpmpound but with only one leaflet) – and alternate. In this species, they are ovate to elliptic or rhombic, to 50 mm long and 25 mm wide with crenate margins in the upper half, aromatic with numerous oil glands. There are stout spines in the leaf axils.
Citrus have conspicuous 3- to 5-merous flowers. In this species, flowers have 3 petals and sepals and are produced solitarily in leaf axils, to about 20 mm wide, with petals white to pink-white with yellow stamens. Flowers are a nice rich purple-pink in bud.
Citrus produce a type of berry called a hesperidium (orange, lemon etc). In this species, the fruit is a cylindrical berry, to 8 cm long by 2.5 cm in diameter, resembling a small gherkin, green to yellow to red on the outside, with caviar-like pulp on the inside which is green to pinkish. Seeds are about 5 mm long.
Citrus australasica seems to me to be pretty easy to grow.
Mine is now about 5 years old, and has been flowering and bearing fruit for the last three years. I would guess that it is a grafted specimen, although it doesn’t say that on the label.
My variety is ‘Crystal’: which as Green skin and fruit with green ‘caviar’ – very fresh, very juicy. I sourced it from Gourmetlimes.com.au.
I have it planted under a large mango tree, north facing, but due to shade from other plants around it, it probably only gets half sun at best. Being a rainforest plant, it seems to be a good spot for it.
I don’t feed it and only water it when I remember, usually when I notice the small flowers on it in spring and think I should help it to set fruit!
In summer, I may see stink bugs which cause dieback of some new growth, but not as many as I get on my orange tree nearby.
I generally only prune to keep it in control and at about chest high. It is VERY prickly and I always wear gloves when working nearby.
Collection of finger limes: This season, I got about 30 fruit off it and have been having them on my breakfast cereal and puddings daily. They are also good on fish and in salads.
For those who also have this plant, the fruit are ripe when they just come off the plant easily when you pull lightly and I read that they do not ripen off the tree. You can freeze them if you have a huge crop.
Can be propagated by seed or by cuttings. Selected forms must be done through cutting.
This species can likely sucker from root zones after fire. However, given its habitat, it is likely too much fire would be detrimental.
Citrus is a genus of about 150 species, naturally occurring from China to Australia and which includes all of the culinary cultivated citrus fruit such as oranges, lemons, madarins and grapefruit. Australia has 8 native species, 6 endemic (Qld and NSW) and 2 naturalised. NSW has 2 native species.
Citrus – from the Ancient Greek word ‘citron’, the first Citrus-type plant to be introduced to Greece.
australasica – Latin meaning “southern-occurring” – likely named due to it been the first Citrus species discovered in Australia. There are now 5 known species.
This species is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Citrus australasica profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Citrus~australasica
Australian National Herbarium – Citrus australasica profile page https://www.anbg.gov.au/gnp/interns-2013/citrus-australasica.html