Australian finger lime, a delicious citrus

Finger lime

Australian finger lime is a thorny citrus variety that produces delicious lemons.

Australian Finger lime facts

NameMicrocitrus australasica
Stock type – grafted
Hardiness – 25°F (-4°C)

Exposure – full sun
Soil – well-drained
Foliage – evergreen
Height – 3 to 10 feet (1 to 3 m), 20 feet or 6 meters if not pruned

Flowering: spring→early summer    –    Harvest: late fall→spring

Its yummy fruits are much sought after by great culinary chefs.

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.

  • Planting finger limeThey need full sun to bear fruit.
  • They like well drained soil.
  • Keep them out of the wind.
  • Occasional light frost is possible but not wished for.
  • Being crowded by other trees or plants with developed root systems like banana trees hinders growth.

In colder areas, plant your Australian finger lime in pots.

  • Repot every 2-3 years, in spring
  • Bring them outdoors in summer, and indoors when temperatures drop to freezing.

Finger lime isn’t a very hardy citrus.

Pruning and caring for Australian finger lime

Remove dead wood regularly and clear the inside branches of your Australian finger lime to let light penetrate to the center.

Wear gloves because their thorns are very prickly.

  • Finger lime careNote: these thorns may also damage fruits in windy areas. Snip nearby thorns off if you want to protect a few specific fruits.
  • Best is to build a wind barrier around the tree.
  • Do the heaviest pruning right after the harvest.

Productive shoots should be pruned off every year, so the tree can replace them.

Watering finger lime

In summer, frequent watering is required, whereas watering can be reduced in winter. Picture above/right: rain doing its part!

  • Finger lime wateringWater as soon as the soil is dry, without flooding the soil.
  • If you’re going to be out for weeks on end in summer, it helps to bury a clay olla pot underground when you’re planting the sapling. This makes watering much easier.

Every two weeks, during the growth phase, add citrus-specific fertilizer to boost fruit-bearing.

Flowering, fruiting & harvesting finger lime

It takes a couple years for flowers to form, and then again two more seasons for fruit formation to set in earnest.

Along the way, you’ll have lots of questions about fruit set and fruit drop – before reaching that happy time of harvest!

Finger lime varieties

Finger lime varietiesFinger lime fruits come in many colors, sometimes even different colors on the same tree!

From wasabi-like green to ruby red to pearl white and purple, it’s a wonder this fruit is only mostly known in restricted circles!

Of all the citrus varieties, the finger lime family has the most colorful and varied fruits.

Finger lime tree problems

Australian finger lime trees are more or less vulnerable to the same diseases and parasites as all the other citrus plants.

Diseases

Disease finger limeGreat news – finger lime is particularly resistant to citrus greening! However, it still suffers from other diseases:

  • European brown rot – lemons rot while still on the Australian finger lime tree
  • Melanose – a fungal disease that attacks leaves, twigs and fruit

Pests

  • Branches and leaves of the finger lime tree are covered with white scale insects.Scale insects – whitish masses colonize leaves and sometimes fruits
  • Aphids – leaves curl up and fall off
  • Katydids and grasshoppers often feed on the fruit
  • Psyllids are another pest that can be found on leaves
  • Thrips – usually attack fruits in shaded portions of the tree. Fruit is still perfectly edible, but skin is spotted and not so appealing.
  • Citrus gall wasp

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.

Cooking with finger lime fruit

When ripe, each finger lime fruit contains hundreds of kernel-sized crystals under pressure under the skin. Upon slicing the fruit, these juicy beads burst out and are ready to nibble or eat directly!

Just like real caviar, each bead will wait until you bite it to release the juice inside. You can sprinkle a little sugar on it to reduce the tartness if need be.

What to cook with finger lime

It is perfect as a wonderful decoration to many dishes, topping for salads, or added on Tex Mex foods, too!

They’re also excellent paired with seafood, to replace the usual sliced lemon on oysters and seashells. Amateurs of sushi will love adding it as a delicious variation. Spread them across grilled fish to hydrate with a delicious touch. Also great with poultry and white meats.

You can pickle the entire fruit, especially for smaller varieties.

Cocktails with finger lime are also a real treat.

Finally, when blended or pressed, the juice works wonders in tarts, ice cream, and flans of all types.

The peel is also edible, like that of kumquat, though not as soft. Use it to replace lemon zests in many recipes for a new delicious experience.

Keeping finger lime

Fruits will keep for up to a month if kept in the refrigerator.

It’s also possible to freeze them whole, but you won’t get the same texture as fresh ones. Incorporate them in Asian soups or noodles, jams, and other recipes where taste is more relevant.

Learn more about Australian finger lime

A deep red australian finger lime hangs from a leafy branch.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!

Finger lime native habitat

This special citrus evolved as a shrub in Australian rain forests (Queensland and New South Wales to be exact). Though part shade is the natural tropical habitat, in temperate climates full sun is needed or it won’t bear fruit well.

Thanks to cross-pollination and diverse growing conditions, a great many varieties exist. Most of them are still awaiting discovery. Wild finger lime trees are often genetically quite different from each other.

Smart tip about finger lime

Pick the finger limes when they easily break off from their branch. Before that, they’re very bitter.


Images: adobestock: job4922, CC BY 2.0: Gastronomia Slow, Malcolm Manners,CC BY-SA 2.0: Kim & Forest Starr, dreamstime: Isgalkin84, Akaphat Porntepkasemsan, Public Domain: Scot Nelson