Home / Australian Finger Lime care / Australian Finger Lime care

Australian Finger Lime care

Australian Finger Lime

(Citrus australasica)

 

Australian Finger Lime tree overview:

Australian Finger Lime are unique fruit that come from a hearty tree.

Australian Finger Limes

Australian Finger Limes

Australian Finger Lime fruit appearance:

As you might expect, Australian Finger Lime fruit are shaped a bit like fingers. However, on closer inspection, I think they look more like miniature zucchinis.

FInger limes may loook a bit like small Zucchini

Finger limes may look a bit like small Zucchini

The fruit range in size from as small as an inch long to as much as 12 cm in length.  This difference in size may be related to the particular cultivar, age/health of the tree and/or local environmental factors.  Much like other fruit trees, thinning of large fruit clusters may improve fruit size.

Finger limes

Finger Lime fruit cluster

Depending on the variety of fruit, the color of the outside-skin ranges from green to red and purple to almost black.   Because finger lime trees are naturally very thorny, the skin of the fruit may be easily damaged by their thorns and wind rub.  However, this is more of a cosmetic issue than anything because superficial abrasions don’t seem to affect the fruit taste.

The texture of the flesh is really unique.  The caviar like vesicles (sometimes called crystals) of the fruit seem to be packed-in under pressure.  When fresh fruit is opened, the tiny vesicles typically spill out of the casing.

Closeup of finger lime vessicles and small seed

Closeup of finger lime vesicles and small seed

Those caviar like vesicles come in a wide range of colors ranging from green, white, yellow, purple, pink and bright red. I have even heard of a blue fleshed variety.

Some trees will also bear fruit with different colors of vesicles in each fruit.  For example, I have a tree that bears fruit with white, pink and/or pink reddish vesicles.  For those varieties of trees, you can’t tell what color the flesh of the fruit will be… “Its like a box of chocolates.”

Different fruit from same tree picked at the same time. Fruit with mostly pink and fruit with mostly white vesicles.

Different fruit from same tree picked at the same time. Fruit with mostly pink and fruit with mostly white vesicles.

The recent popularity of the fruit had prompted investment in genetic crosses and improved selections which are currently under development.  More colors and sizes to come.

 

Australian Finger Lime taste:

The wonderful uniqueness of this fruit comes from the caviar like texture of the flesh. These multiple small round vesicles are a stunning gustatory experience.  If you have ever had a “California Roll” with fish eggs on it… well the fruit vesicles are lot like those eggs.

The fruit is tart/acid – on the same level of a typical lime. However, the total flavor is not exactly like a lime. There more of a floral element to the flavor.  Sometimes, the fruit almost tastes like an unsweetened “Sweet Tart” candy.

 

Fruit Use:

The Australian Finger Lime is gaining popularity among creative chefs and curious foodies.  The bright flavor of the “lime caviar” fruit seems to be a natural fit as a seafood garnish.

I have tried to add it to drinks, but unfortunately the vesicles basically sink to the bottom of the glass resulting in an intense tart surprise at the end.

Surprisingly, even though it is a powerful flavor, many like to eat the fruit raw (including myself). Adding sugar makes the fruit taste like sweet-tart candy.

I have also heard that the finger lime peel can be dried and used as a flavoring spice… although I have not tried that.

FInger limes and foliage

Finger limes and foliage

 

Australian Finger Lime fruit season: 

In California the flowers seem to have a prolonged bloom cycle and I have  seen them mainly from April to August.  However, I have seen flowers as late as October. I have been picking ripe fruit from May to November.

Like other citrus, finger lime fruit must be fully ripe when picked because they do not ripen off the tree.  Unripe fruit will be bitter.

The easiest way for me to tell if the fruit are ripe, is to give a gentle tug. If the fruit detach easily then they are probably ready. Others have written that the fruit “feel full” when they are ripe but I don’t exactly know what that means.  Other than the obvious tasting of the fruit, another way to confirm ripeness is to split the fruit open and then gently squeeze. If the fruit is ripe, the vesicles should come out separately and freely.

Grafted finger lime trees may begin fruiting at 3 years of age, but larger quantities of fruit are usually seen around 6 years of age.

Finger lime vesicles pour out when fruit is ripe and split open

Finger lime vesicles pour out when fruit is ripe and split open

Landscaping: 

Foliage:

Australian finger limes typically have dense foliage with multiple small leaves. Therefore, they may provide some privacy if planted strategically. The trees also have many small thorns, so they are not the best option for the border of walkways or in high traffic areas.

Dense finger lime foliage

Dense finger lime foliage

Tree appearance:

Different finger lime tree cultivars have a variety of shapes and sizes.  Some finger lime trees can grow as tall as 6 meters in the wild. Try to get as much info as you can about the particular growth habitat of your finger lime so you can best optimize your landscape.

The Australian government has a document that outlines the characters of several different varieties:

  • Citrus australasica ‘Alstonville’ – a tall growing shrub producing dark green-black fruit with a pale green flesh.
  • Citrus australasica ‘Blunobia Pink Crystal’ – a compact medium shrub producing green-brown fruit with a deep pink flesh.
  • Citrus australasica ‘Durhams Emerald’ – a medium open shrub producing black fruit with an emerald green pulp.
  • Citrus australasica ‘Judy’s Everbearing’ – a tall shrub producing green-brown to maroon fruit with a green to dark pink flesh
  • Citrus australasica ‘Pink Ice’ – a medium growing shrub producing reddish maroon fruit with a clear to pink flesh

Reference: Growing Australian native finger limes

Growth speed:

I have read that Australian Finger Lime trees are slow to establish and may show little sign of any growth for the first year after planting.

However, this is definitely not my experience.  For example, I received a potted finger lime tree as a gift from a friend.  That tree was so root bound that there was basically no soil left in the pot.  This particular plant was in one of those beautiful painted curvy ceramic pots and I wanted to extract the tree without breaking the container… so I could give the container back to my friend. Therefore, I was forced to sacrifice a lot of the peripheral roots to free the roots from the confines of the vessel.   (Note, in my extraction, I was otherwise very gentile and cautious to keep the core root ball intact).

From there I just followed my typical planting process. To my delight, the tree almost immediately started putting out new growth.. and now a year later the tree is over twice the size it was at the initial planting.  Therefore, at least from this experience, this plant seem much heartier than your typical citrus.

Similar to lemons the leaves are dark purple when young and turn green as they mature.

Young purple finger lime leaves

Young purple finger lime leaves

Flowers:

The flowers are rather tiny and are only really appreciated on close inspection.  Therefore, this is not a “showy” plant.  In fact, the numerous dark sausage-like fruit hanging on the tree is not exactly ornamental. However, a tree full of fruit is a bit of a conversation piece, especially if you have friends that can appreciate the unusual.

Tiny finger lime flowers and flower buds

Tiny finger lime flowers and flower buds

More finger lime flowers

More finger lime flowers

Soil:

In its natural habitat, finger lime trees grow on a wide range of soil types.

However, I suspect they will be a lot happier if you give the soil some extra love. Therefore, I do what has worked for all of my other trees; I aggressively augmented the soil with grow mulch/compost, and inoculate the roots with Micorriza.  Note, the soil must be well draining with these guys. Click here for the planting method that I have used with great success.

Finger lime leaves

Finger lime leaves

Water:

Australian finger limes are said to be drought tolerant. Regardless, I water most of my citrus trees the same… which means I schedule deep watering around 2x (sometimes 3x) a week in the summer (after they are established).

For established trees, I cut way back on the watering in the winter… mainly because winter is usually our wet season in California and you can get away with not watering.

Covering the ground around the base of the tree with a nice layer of wood mulch will help to retain moisture in the summer and help to keep the roots cool.

 

Sun:

In their natural habitat, Australian Finger Lime trees typically grow as an understory shrub or tree.  Therefore, they are built to grow in the shade. However, they also seem to do great in full sun and this is how most commercial growers plant them.

Fertilization: 

I have not seen any specific research on finger lime nutrient requirements.  None the less, finger limes seem to need a lot less fertilizer than other commercial citrus varieties.  Many growers are using only about 25–30% of the total annual amount of fertilizer used for other citrus varieties.

To prevent fruit abortion, some have recommended avoiding fertilizer from the time of flowering to the point when the fruit are 1 cm long. Others have reported that over fertilization can cause limb dieback. I have not noticed any of this.

Otherwise, I try to fertilize all of my citrus trees from late winter to mid-summer. The rational is that I don’t want to encourage young leaf growth in the winter because of the risk of cold damage to the susceptible young leaves.  On the other end, I don’t want to encourage excessive young growth during leaf miner season which starts around July.

I generally use a balanced fertilizer such as 15-15-15 on my citrus and apply it in 4 doses during the fertilization season described above. I also give a single dose of citrus specific micronutrients in the spring.  I have been trying different brands of citrus micronutrient fertilizer, but this organic one with a money back guarantee sold on Amazon looks really great.

Lately I have also been adding in all kinds of other goodies as a top dressing over the root zone such as mushroom compost; grow mulch, worm castings, etc. I am getting the sense that citrus like the variety.  See my earlier post for how to get free compost.

 

Temperature:  

When it comes to temperature, I am not aware of any specific research on finger limes. However, I would basically treat them like other citrus in this regard. Plant them in a warm sunny location and try to avoid areas with extreme hot or cold winds. They are likely able to tolerate a light frost, but that is just my conjecture.

In general, just about any citrus will freeze when the temperature drops below 27-28°F.

In my years in San Diego, frost protection for my citrus has not been necessary.  Sure, they dont like the cold, but they get by without any special care. However, cold/frost protection is very important in cooler climates.

For more information about the lowest temperatures that you can expect in your specific area, check out my article “Climate Zones: What can I grow in my yard?”

 

Pollination:

The flowers of finger lime trees seem to be a bit small for bees. Perhaps other insects or wind play a greater role in pollination of these flowers. Regardless, curved/deformed fruit are likely the result of poor pollination.

Curved finger lime fruit likely from poor pollination

Curved finger lime fruit likely from poor pollination

Propagation:

Most finger lime trees that you would buy are grafted. The trees grown from seed have unpredictable (not necessarily true to type) fruit quality. In addition, seed grown finger limes may be slower growing and can take longer to bear fruit.

 

Citrus Pests: 

Finger limes are susceptible to most of the same pests and diseases as other citrus.

A common disease reported to affect finger limes in Australia is melanose (Diaporthe citri).  This is a fungal disease that causes dark brown to black spots on the foliage, twigs and fruit. Spores of the fungus develop in dead citrus tissue and are released by water and/or rainfall. The fungus affects all citrus varieties and the incidence of melanose usually increases as trees age and the amount of dead wood in the canopy increases.

On the positive side, finger limes are reported to be highly resistant to Phytophthora citrophthora root disease.

The major pest for all of my citrus is the Citrus LeafminerClick here to see my post about the diagnosis and treatment of Citrus Leafminer. 

One of the most important things to do is to keep the ants out of the tree which often bring aphids, scale and mealybugs with them.  A great way to do this is to use Tanglefoot.  However, don’t apply Tanglefoot directly to the bark because the thin bark of citrus can be easily damaged this way.  Create a skirt of masking tape around the trunk of the tree (with the sticky-side out) or buy the Tanglefoot guard paper wrap.  Then add the Tanglefoot on that skirt/paper.

Citrus Greening AKA Huanglongbing (HLB) is currently wreaking havoc in Florida.  All citrus growing states are on high alert and most are under quarantine.  The disease is incurable and will usually kill a tree within several years.  The disease is spread by the insect known as the Asian Citrus Psyllid. Leaves with HLB disease have a blotchy yellow pattern that is not the same on both sides of the leaf.  If you suspect this disease, it should be reported to the California Department of Food and Agriculture hotline at 1-800-491-1899.

Like Tahitian limes (AKA Bearss limes), finger limes are reported to occasionally suffer from stylar end breakdown (SEB). This is not really a disease but can be annoying. I wrote more about this process in this article on Bearss limes.

 

Miscellaneous:

  • According to the “Swingle system” of taxonomy the finger lime is not part of the genus citrus, but in a related genus Microcitrus.

 

About Thomas Osborne, MD

Dr. Osborne is a Harvard trained Radiologist and Neuroradiologist who loves to share his insight about medicine and gardening.

28 comments

  1. Great article – I enjoyed reading it. I have recently started taking care of finger limes and articles like this help a lot. I look forward to updates of your progress 😉

    • Thomas Osborne, MD

      Hey Steve.
      Thank you for the note.
      Ill def update the post as new insights arise.
      Looking forward to hearing about your progress as well.
      Thanks,
      Tom

  2. Ok so you convinced me I want one. Where can I get them?

  3. I am a farmer from Vietnam. I am really excited in Finger Lime and I am considering choosing it for my next crop.
    Could you please provide me further info about purchasing and pricing? Are you providing seeding or grafted or anything else? Is there anyway for shipping to Vietnam?

    Under Vietnam’s climate, is the tree growing up properly? How long would it take for a harvest? (both seeding & grafted one)

    Again, thank you so much for your time!

    • Thomas Osborne, MD

      Hi
      Thanks for the note.
      The finger lime is a very interesting and unique fruit and would be a great addition to a citrus orchard.

      As far as purchasing
      There are a few things to consider.
      There is a very big and important disease hitting all citrus plants called “Citrus Greening”
      As a result, many countries are on strict quarantine and don’t allow citrus plants in from other countries.

      However, if you could bring them into Vietnam, I would look to your neighbor to the South for purchasing plants (Australia).

      Once established, healthy plants start to fruit when a few years old and about 3-4 foot tall.

      Good luck!
      Tom

      • Hi Tom,

        Thank you so much for your info!
        In case i would like to purchase both seeds and grafting trees, is there anyway to ship them? And what is the price for each?
        Also, if I go ahead with this, may I receive a “certificate of health” (Phytosanitary certificate I think) from the seller?

        Again, thank you so much for your advice!

        Best Regards,
        Phil Nguyen

        • Thomas Osborne, MD

          No problem Phil

          I would think that a finger lime tree should cost you about the same or a little bit more than a typical citrus… The only reason why they would cost a little bit more is because they are not as common and a bit harder to come by. However, these trees are rather hearty.

          Each country, (and even regions within a country), has their own laws and regulations about this stuff. A reputable seller that is certified to ship to your country/region should know the details. You might also be able to check in with your local government agricultural department for the details. If the plants arrive w/o the proper documentation they could be sent back or destroyed by the agricultural department. Worse yet, if the plant is infected with something (like citrus greening) it could spread disease to the rest of the country.

          As far as seeds, they should be cheap… I would think.
          But I have never priced them out. Basically get some fruit and you will get free seeds to plant.

          However, I would caution; there is a real risk that the tree that grows from the seed may produce fruit that is not quite the same as the fruit that it came from. That could be the fun and interesting part too. However, if you had your heart set on a particular color, size then its risky… and it will take a while for the tree to get to fruiting age.

          Good luck!

    • Hi !

      My name is Loc, I’m also from Viet Nam. At this time, I have 10 grafted trees with troyer rootstock. If you are interested in this tree , pls contact me at email: 0909 006 552 or email: locnguyen2210@gmail.com

      Thanks

  4. Dear Thomas Osborne, MD

    Although I can import trees from Australia to Viet Nam, but I really don’t know the climate in VN ( about 30-38 degree celsius ) that can make trees bearing fruit or not

    If you have any advises , please show me!

    Best Regards,

    • Thomas Osborne, MD

      Thanks Loc
      Agree climate is an important consideration.
      In addition, the climate varies dramatically in different parts of Vietnam depending on the distance from the ocean and altitude-mountains. This would be an important discussion to have with a seller before purchase.
      Thanks,
      Tom

      • Dear Tom

        Do I need to fertilize my half-year-finger lime tree? And if, what kind of fertilizer i can use?

        Thanks Tom

        • Thomas Osborne, MD

          Hey Loc
          This is a tricky question to answer.

          Overall, it seems that finger lime trees need less fertilizer than other citrus… How much less is up for debate.

          I have planted in good soil and I am using about 1/4 dose the amount of citrus fertilizer that I would use on a similar sized tree and it seems to be working well for me.

          Another angle would be to look at the leaves. The leaves are a good indicator to pay attention to as you are trying to figure this out for yourself and your soil conditions.

          For example, if the leaves look light green – yellow you might be low on nitrogen. If the leaves are dark green and burnt on the ends, you might have too much nitrogen with salt burn. (Of course citrus need more than just nitrogen… I was just using that as an example of the most common deficiency).

          Hope this helps
          T

  5. Hi Thomas,

    My name is Wagon, just like you being obsessed by usual plants among which is fingerlime?

    Can this shrub possible grow in Malaysia? Do you have contacts South Under where they are able to provide

    grafted fingerlime?

    Your help and advice is much appreciated

    Wagon ( Singapore)

    • Thomas Osborne, MD

      Hi Wagon.
      Thanks for the note.

      I dont know how well the finger lime grows in Malaysia but I would think you would have a good chance that it would do just fine. The plant requires similar growing conditions as a typical citrus tree but I think that this plant tends to tolerate/prefer slightly dryer conditions than your typical citrus.

      Since you are relatively close to Australia, I would think that you would have good access to plants. (Australia has the greatest variety of finger limes because this tree is nave to Australia).

      Perhaps another reader might know some local connections for you.

      Best,
      Tom

  6. Hi Dr. Osborne,
    I live in Washington State, USA. I sampled finger limes at a culinary event last year and fell in love with them. As soon as I got home I went online and ordered one.I have pampered it for the last year indoors for the most part. On warm days I move it outside for some sun. I was so excited to see many little purple buds. One even bloomed. Our summer is now coming to an end and there are still many buds that have not bloomed. I have two questions, 1) Do I need to create an environment to prompt the buds to bloom, if so what would that be; and 2) How do I manually pollinate the blooms?

    One other thing I’ve noticed with my tree is that the limbs are flat and twisting not round like other trees. I’ve not read anything about this. It may be that I am trying to grow citrus in an area that doesn’t typically grow citrus.

    I appreciate any advice you can offer.

    • Thomas Osborne, MD

      Hey Liz
      I admire your ambition and perspective.
      I try to push the limits on what I can grow in my local environment all the time… More than a few failed attempts.

      Growing in containers:
      This is really a topic/article by itself.
      However, for the most part, dwarf varieties of citrus do grow fine in containers (but they will need special care).
      I dont know if there are any varieties of finger lime… so this could be a limitation.
      On a personal note; a friend of mine gave me a root bound finger lime that was stunted and sickly looking.
      I put it in the ground with some TLC and the next year it was 2x the size and fruiting.
      So it would seem that it can be hard to grow in containers.

      Buds:
      I dont know of any tricks to make the buds open faster.
      However, flowers on a lot of plants will fall off when a plant is stressed. It is a sensitive time for plants.

      Pollination:
      Basically you want to get the pollen from the anthers (the little projections around the center of the flower)
      and move that pollen to the stigma (the top of that one projection in the middle of the flower)
      A soft small watercolor paintbrush or q-tip should do the trick.

      Good luck,
      Tom

      • Thank you so much for your reply. I may have been a bit too optimistic to try to grow a lime tree in our environment but I’m committed to do my best to keep it healthy.

        I appreciate your advice and will check periodically with how it is doing.

        Thanks Much 🌿
        Liz

  7. Hello mr Osborne,

    I just bought 200.000 sqm of land in Vietnam, in a dry area, although 5 min from the sea…
    It is very reddish sandy soil, quite rich although needs to be proper examinated. And treated if necessary. There is water supply sytem on the land.
    I am wandering what is the numbers of finger lime trees to be planted per hectares.
    What should be the most exclusive fingerlime type to plant, considering that i want to export the production and if the surface of the land is big enough for a nice production.
    Further more, what is the average production of a tree in its 3/4 years.

    Best regards
    M. Baltz

    • Thomas Osborne, MD

      Hi M. Blatz
      Congrats on your new farm.

      I am not sure of an optimal number of finger lime trees you can grow in an area.
      The problem is that there is a variation in the shape and size of different types of finger lime trees (tall, short, etc).
      The intrinsic shape/size of a tree will impact how close you can grow them together.
      So the answer will depend on what variety you grow.
      Another consideration is that these plants are very thorny and if you grow them too close you could find yourself cut off from an area.
      Perhaps another reader has some insight… but if I was to take a general stab at it, I would say plant them at least 6-10 feet apart.

      There are a lot of varieties and many more varieties are being developed.
      Heres is a reference that provides some specifics about some different varieties.

      The production/yield will also depend on the specific variety as well as growing conditions.
      So… again it depends.

      Good luck!
      Tom

  8. Really nice article!
    Any tips were I could find some seeds?

    • Thomas Osborne, MD

      Thanks Georg
      I am going to try to plant some seeds from the fruit and see how it goes.
      Of course, there is a big risk that the fruit will not be true to the mother plant.. and it might take a long time to find out.. but whatever, its a finger lime. The fruit is prob going to be interesting regardless.

  9. Hi Dr Osborne,

    Nice concise article.
    I’ve just purchased four named finger lime cultivars, about 2ft high in the pot. One began to bloom.

    I also had an MRI that revealed a small 1cm pancreatic intraductal papillary mucinous tumor in the tail of the organ (based only on the MRI).

    If you were me, wouild you remove the flowers since the plant is fairly small and/or the tumor for the same reason?

    Thanks,

    Bob

    • Thomas Osborne, MD

      Thanks Bob

      Two great questions.

      Finger lime question:
      In general, I suggest removing flowers of newly planted trees so they can divert their energy to getting established/building a strong root system etc.

      Pancreatic cystic tumor:
      I try to separate my medical world from this site… and in general try to hold back on providing medical advice in this type of forum. A lot of factors make giving advice over the internet problematic. One tricky part is doing so with markedly limited information such as not having the images or lab results to evaluate.

      In general, there are several types of cystic pancreatic lesions. Sometimes there are findings on MRI etc, that help with making the correct diagnosis. However, benign, premalignant and malignant lesions can also sometimes have similar appearances on MRI which can make a specific diagnosis challenging… This is particularly important because the correct diagnosis guides the best treatment. There are also blood tests that may support one diagnostic option more than another.

      Treatment options may also be impacted by the location of the lesion (main duct or branch duct), as well as by specific imaging features/look of the lesion (such as Tanaka criteria). Other factors, such as ones general health and overall goals, and details of the specific situation will also help guide treatment decisions. I would defer to your clinical team of doctors, etc who would be in the best position to guide you in the right direction. When in doubt, getting a second opinion is always an option; and I would encourage anyone to see another reputable certified medical specialist/doctor if there are persistent concerns about the treatment direction.

      More info:
      Here are a few references that may be utilized to help guide the clinical treatment decisions for cystic pancreatic tumors:
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562774/
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4374202/
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4433138/
      http://www.ajronline.org/doi/full/10.2214/AJR.12.8862
      http://www.pancyst.org/files/pdf/IPMN_consensus_guidelines.pdf
      http://pubs.rsna.org/doi/full/10.1148/rg.256045161

      Best,
      Tom

  10. Lucille Stevens

    Hi Pbil, I have a 5 year old finger lime that was setting fruit and doing really well i went on vacation for 1 wk and had a neighbor water my plants. When i returned, my tree was just about dead. All the leaves were dry, most of the branches were dry. I scrapped the trunk and it is still green. I water every day in hopes that it will put out some leaves. Shoud i give up on it.

    • Thomas Osborne, MD

      Hey Lucille
      Wow, that is an amazing and sad story.
      Finger lime plants are very drought tolerant… so it is surprising to hear that a single week could do so much damage. Esp for a 5 year old plant that would be expected to be rather established. Makes me wonder if something else is going on.

      None the less, sorry to hear about that.

      If I was in your position, I would do the following.
      Inspect the plant really well.
      See if there are any clues that may suggest another issue (damage from bugs, animals, bacteria/fungi, people, over fertilization, etc).
      Inspect any adjacent/nearby plants for similar problems.

      Then I would get a clean pair of pruning sheers/bypass trimmers and a pair of very-thick gloves.
      The thick gloves are because (as I am sure you know) these plants are very thorny.

      I would trim back all the clearly dead branches until you get to healthy wood.
      After that, and depending on what you see, I might consider spraying with some organic insecticide and/or antifungal.
      The reason is that there are some fungal infections of citrus that will cause limb die-back.

      Good luck and let us know how it goes.
      Thanks,
      T

Leave a Reply

Your email address will not be published.

Scroll To Top