Australian finger lime is a thorny variety related to the citrus family, that produces delicious lemons that are very sought after by great culinary chefs.
Australian Finger lime facts
Name – Microcitrus australasica
Height – 3 to 10 feet (1 to 3 m)
Exposure – full sun
Soil – well-drained
Foliage – evergreen
Flowering – March to July
Harvest – November to March
Planting Australian finger lime
It is only possible to plant Australian finger lime in the ground in mild-wintered areas because they can’t survive freezing temperatures and strong frost spells can be fatal to them.
- They need full sun to bear lemons.
- They like well drained soil.
- Being crowded by other trees or plants with developed root systems like banana trees hinders their growth.
In colder areas, plant your Australian finger lime in pots.
Repotting your Australian finger lime
Potted Australian finger lime cannot extract the nutrients they need from the ground.
So the pot and soil you have put in it are their only source of food for them to stock up and grow.
Re-potting is thus critical.
- Re-potting takes place every 2 or 3 years in spring.
- Choose high-quality citrus-specific or planting soil mix.
- Double-check that the bottom of the pot has a hole drilled in.
- Place a bed of small pebbles or clay marbles at the bottom of the pot to ensure excellent drainage.
Potted Australian finger lime trees in winter
Growing Australian finger lime trees in pots is most adapted, because it makes it possible to bring the lemon trees to a well-lit spot where it doesn’t freeze in the winter.
Australian finger lime trees aren’t indoor plants, and can’t bear staying in a heated environment all year round. They need relatively lower temperatures from October to May.
It is important to place them in an unheated greenhouse for instance, where the temperature never drops below 32°F (0°C).
- If you’re looking for citrus plants that cope well with growing indoors, check out calamondin trees.
Pruning and caring for Australian finger lime trees
When pruning Australian finger lime trees, wear gloves to protect your hands, because their thorns are very prickly.
Shoots are pruned every year, so that fruits may benefit from the greatest amount of sap.
Prune the shoots to give the Australian finger lime tree a regular, harmonious shape.
- Cut each new shoot back to more or less half its length, taking great care to cut just above a leaf.
- This will result in your lemon tree keeping a nice, tight shape.
- You might need to do this several times a year.
Remove dead wood regularly and clear the inside branches of your Australian finger lime to let light penetrate to the center.
Watering your Australian finger lime tree
In pots, Australian finger lime trees dry up much faster than if they were planted in the ground, so it is essential that they be watered regularly.
In summer, frequent watering is required, whereas watering can be reduced in winter.
- Water as soon as the soil is dry, without flooding the pots.
- Avoid all heat sources such as nearby radiators, because this could dry your tree out.
Every two weeks, during the growth phase, add citrus-specific fertilizer to boost fruit-bearing.
Check our video with expert guidance on Australian finger lime trees
Harvesting Australian finger lime
Harvest season is usually November to March.
You will ensure the lemons mature best by protecting the tree from freezing, and keeping the soil around it slightly moist.
Diseases commonly found on Australian finger lime trees
- European brown rot – lemons rot while still on the Australian finger lime tree
- Scale insects – whitish masses colonize leaves
- Aphids – leaves curl up and fall off
Citrus gall wasp
This tiny wasp only a few millimeters long lays eggs in fresh shoots. They commandeer growth of the branch to form a gall and then hatch. This pest is currently only found in Australia, although possible sightings in New Zealand indicate it may be spreading further. The best way to deal with it is to prune out gall-infected branches before any adult citrus wasp hatches.
Australian finger lime is actually the original host for citrus gall wasp. However, when planted with other non-native citrus, it will prefer laying on lemon, grapefruit, and mandarin citrus trees instead. Having been exposed to the parasite for longer, the native tree has developed a somewhat higher defense mechanism. Indeed, not all eggs and larvae on an Australian finger lime are able to reach maturity.
Learn more about Australian finger lime
Australian finger lime trees are exceptional – and expensive – fruits, because their price can fetch upwards of 300 dollars a kilo.
Their juice is trapped in tiny capsules that look like pearls, and burst in the mouth, releasing an explosion of flavors like lemon, citrus and grapefruit: this is the “lime caviar” that great chefs crave!
Smart tip about Australian finger lime
Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Open finger lime fruit by Gastronomia Slow under © CC BY 2.0
Mealy bugs on finger lime tree by Scot Nelson under Public Domain
Ripe finger lime on tree by Malcolm Manners under © CC BY 2.0