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Nagami Kumquat: growing information

Nagami Kumquat

(Fortunella margarita)


Nagami Kumquat Overview:

If you like sweet and sour this nugget sized citrus fruit is for you.  This is a rather cold tolerant citrus tree that just gives and gives nearly all year long.

Nagami Kumquat fruit tree

Nagami Kumquat fruit


Nagami Kumquat Fruit:

Nagami Kumquat Fruit Appearance:

The fruit is the size and shape of a large olive.  However, the outer color and texture is similar to an orange.  The plant is very prolific and has fruit nearly the whole year.


Nagami Kumquat Taste:

This plant is unusual in the citrus family because the skin is edible.  In fact the skin is the sweet part of the fruit and is sometimes the only thing eaten.  The flesh is juicy but very sour and acidic, similar to the flavor of a lemon.  The fruit is ripe when the majority of the skin is orange with perhaps a small hint of green remaining at the top.


Nagami Kumquat Fruit Season:

I have read that the fruit matures late in winter.  However, I don’t think my Nagami Kumquat trees have read the books because there are fruits on this amazing tree all year.

Nagami Kumquat inside

Nagami Kumquat skin cut to show the inside of the fruit

Landscaping use:

  • The Nagami kumquat is a slow growing large shrub or small tree with an overall rounded shape and dense evergreen foliage.
  • Because the Nagami kumquat is among the most cold tolerant of all citrus, it could possibly be planted in lower parts of your yard that have a tendency to collect cool air.  However, the fruit is said to be sweeter when it is grown in warmer environments.
  • Nagami Kumquat has white fragrant flowers which and are similar in appearance to other citrus flowers.  Nagami Kumquat trees almost always bloom in the summer but I have noticed that the plant has a tendency to flower periodically throughout the year.  The small orange fruit make the plant very ornamental.  The plant is very prolific. In the main fruiting season (winter) there are so many fruit on the trees that I have that the branches completely bend over.
  • The Nagami Kumquat is also used in Bonsai and the plant is definitely suitable for large pots.
  • Prune in winter.
Nagami Kumquat

Nagami Kumquat branches bent from the weight of the fruit


Nagami Kumquat Tree Soil:

The Nagami Kumquat does better with slightly acidic soil.  Augmenting with lots of organic material will always help your citrus.

Click here to see my 6/9/13 post on the best planting technique to avoid transplantation shock.



  • Water on the same cycle as other citrus; 1 to 3x/week in the summer depending on your local micro-climate.
  • Infrequent deep heavy watering is much better than frequent light watering.
  • You can cut way back on the watering in the winter after the tree is established.
  • Mulching helps to keep the soil from drying out.
  • Citrus don’t like standing water.



  • Full


Nagami Kumquat Fertilization:

  • The tree is more susceptible to zinc deficiency that other citrus.  However, like all citrus it also needs other micronutrients.  I add micronutrients to the topsoil in the spring.
  • I also provide a balanced fertilizer throughout the growing season (4x/y).  In general, I have noticed that  all of my citrus appreciate an assortment of different types of fertilizers throughout the year.  Throwing in a random assortment of organic fertilizer whenever you have it is always appreciated (compost, worm castings etc).



  • Because it goes into a dormant non-growth stage sage in the winter, the plant is one of the most cold tolerant of all citrus. I have read that the Nagami Kumquat is able to withstand temperatures as low as 14F!  But I wouldn’t recommend pushing that chilly temperature limit.
  • For more information about the lowest temperatures that you can expect in your area, check out my article “Climate Zones: What can I grow in my yard?”



Susceptible to the usual citrus pests such as the citrus leafminer.

For more information, please see my 6/20/13 post for diagnosis and treatment of the Citrus Leafminer. 


Food use:

  • If you like sour, you can just pop them in your mouth peal and all.  If you eat the fruit all at once it is a powerfully and intense hit to your taste buds. When I eat the Nagami Kumquat fruit this way, it almost reminds me of Gatorade gum.
  • Some people will just eat the rind because that is the sweet part and toss the sour juicy center.
  • Nagami Kumquat fruit is also used to make preserves, marmalade and candied.
  • Garnish drinks/cocktails.
  • The sour juice can be made into a lemonade like drink.
  • Cut the whole fruit into thin slices for salads.



About Thomas Osborne, MD

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


  1. I planted a Kumquat for the first time last year. Fukuqui or something. Anyway, After doing well for a few months, it wilted and died I thought. Reading your article I guess it went dormant and perhaps it will spring back to life now that the weather is warmer in San Jose. I noticed that water drains away fast but I suspected it was because there was a Gopher hole right under the roots. The Mandarin orange right next to it, is still thriving and never lost its leaves in spite of the early cold snap we had in Dec. So I look forward to the next few weeks to see if my Kumquat comes back to life. I have already bought another Red Baron Peach to replace it if it dies. The Red Baron is to keep the JH Hale Peach company!

    • Thomas Osborne, MD

      Hey Sateesh
      Yea, Kumquats do slow down in the winter. As a result, they don’t tend to put out new growth in the colder months-and it is this new growth that is most sensitive to cold damage. Because of this particular growth pattern, Kumquats are more cold tolerant than other citrus.

      However, Kumquats don’t go dormant like your peach or apple trees do. In the winter, Kumquats should still have lots of leaves. In fact, my Kumquat trees are currently packed with fruit.

      Therefore, if your Kumquat is looking wilted, I fear that something is more concerning is going on. The nearby gopher hole could potentially be the sign that bad things are happening to your Kumquats roots. I have seen gophers take out an entire tree and leave an adjacent tree of similar size and make untouched. Sadly, I have lost many trees to those rodents.

      • You’re probably right Tom, but just in case, I dug up the Kumquat and planted it in a new hole with lots of mulch, top soil and fertilizer. The root ball still looked alive so there is hope yet. I replaced the Kumquat with a Red Baron peach which is right next to the JH Hale so pollination should not be a problem. I am eager to see results in the next few months. Will keep you posted. Thanks for your advice and support.

        • Thomas Osborne, MD

          Good job Sateesh. Your doing exactly what I would be doing.
          I would also err on the side of over watering in this critical time.
          I am sure you have already done this as well, however, I would also do a close inspection for bugs, those suckers can do more damage than many give them credit for.

  2. Two months after bringing my very leafy, full green Kumquat tree into a constant ( no lower that 55′ ) temperature home, all the leaves have fallen of. I have not fertilized at all. there are 10 green fruit on the tree. Is it dormant or dying…..? No gophers, no other plants failing in home…..can You help…?

    • Thomas Osborne, MD

      Hi Paul.
      That is a sad story.
      I am not exactly sure what is going on but there are a few possibilities to consider.

      If your tree is at the ground floor, then it might be colder down there then one might expect. Cold air is heavy and collects down low, esp at night when there is not a lot of movement and it is extra cold anyways.

      Potted plants dry out easily and winter air is often dryer than any other time of year.

      Root damage:
      Moving a big potted plant around can shock the little root hairs. These little hairs do most of the work for a plant and damage to them can sent a plant into a tailspin.

      Plants dont like change. A change in sunlight in addition to any of the above can just upset a plant. A combination of many small changes can add up to a big deal.

      There are likely more possibilities to consider, but its hard to tell without being there.

      What to do:
      Remove all of the fruit. They will only suck more energy away from the plant.
      Watch soil conditions closely.
      Keep plant in a safe place above ground level.

  3. Hello
    I am doing research on Kumquat fruit.
    How do you know this fruit is and what it is a sign of maturity.
    If you are able to make the resources available to me please thank you

    • Thomas Osborne, MD

      Hi Arsalan
      Thanks for the note.

      Optimal Kumquat fruit ripeness:
      To some degree, the optimal time for fruit ripeness depends on your personal preference.
      The longer you wait to pick the fruit, the sweeter the fruit gets.
      However, if you wait too long then the fruit can fall off the tree and/or shrivel up.

      For me, I find the best time of ripeness is when you have the following:
      * The fruit is orange in color… the darker the fruit the sweeter.
      * The point where the fruit is attached to the tree can sometimes be a tad green and still be good. However, the fruit will be sweeter as that area turns yellow.
      * The fruit will be less firm to the touch as it hits maximum sweetness.
      * The fruit will pull off the branch fairly easily when optimally ripe.

      Would you like more information regarding your resource question?


      • Hi Tom
        Thank you Tom for the good tips I’ve provided.
        Sources can provide me with a debt that is acceptable in scientific research I can put it in my research.

        • Thomas Osborne, MD

          Hi Arsalan

          The majority of the information I have about growing Kumquat’s has been obtained from two major sources:
          * Years of personal experience
          * Discussions with nursery owners and local growers.

          Unfortunately, this is not typically the group of people who write scientific papers on these topics.
          There are some commercially available books that are nice to use as a reference, such as:
          http://www.amazon.com/gp/product/0376039183/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=0376039183&linkCode=as2&tag=tastylands-20&linkId=WHFT4W5QVZBJA3YW“>Western Garden Book of Edibles: The Complete A-Z Guide to Growing Your Own Vegetables, Herbs, and FruitsReply

          • Hi Tom
            Do you think you can or using image processing techniques using near-infrared investigation to determine Kumquat?
            Thank you very much

          • Thomas Osborne, MD

            Hi Arsalan
            That is a very interesting and advanced question.

            Basically Near-infrared is a form of light that we cannot normally see.
            This specific part of the electromagnetic spectrum is from about 800 nm to 2500 nm.
            With specific instruments that allows us to see near-infrared, we can tap into a wealth of additional information about something.

            What is it used for?:
            Near-infrared spectroscopy (NIRS) has a lot of scientific applications.
            NIRS is used in medicine, astronomy and agriculture (to name a few).
            Specifically, NIRS can be used to non-invasively determine the quality of food products ranging from fruits, grains, meat and eggs.
            NIRS can also be used remotely (from far away) to evaluate forests and soils.

            Ripe fruit:
            Since a ripe fruit is expected to have a specific near-infrared signature, then you may see differences with NIRS.
            The specific sensitivity range of your NIRS instruments would make a difference.
            Therefore, you would have to get the right NIRS tools with the correct sensitivity.
            Potentially subtle differences may be difficult to detect depending on the scale you are looking at.

            Scientific Papers:
            There are a lot of papers out there on this specific field of inquiry.
            Below are a few examples of the types of NIRS fruit articles that you may find on an internet search.




            Good luck!

  4. Hello
    I am doing research on Kumquat fruit.
    How do you know what the fruit is ripe and it is a sign of maturity.
    If you are able to make the resources available to me please thank you

  5. I had a great little tree foe 3 years that did wonderfully. Last year it started dying from the top down. I live in North Florida and we had no big freezes. Any ideas? The neighbors and I miss the tree. Plan to replace it.

    • Thomas Osborne, MD

      Hey Judy
      What a bummer. Sorry to hear that.
      Kumquats are one of the most cold tolerant citrus, so I also dont think it is from a freeze.
      Not sure what the cause could be at the moment… Do you happen to have any pictures?

  6. hi thomas
    I bough two nagami kumquat about two years ago and I transplanted them in our backyard. I live in vally in california. when i bought them they had many fruits, but since than they haven’t given any more fruit and the leaves fall. I been giving them chicken manure, and stem manure and vitamin b but they are still only having some leaves.

    • Thomas Osborne, MD

      Hey Sean
      Thanks for the question.
      Sorry to hear about your kumquat leaf loss.

      There are many potential causes of major leaf loss.
      However, in my experience most all of them relate to plant stress and quite often that stress is some how related to water/the roots.

      A few more-specific things to think about.

      Transplantation shock:
      Major leaf loss can be a sign of transplantation shock.
      Transplantation shock usually occurs as a result of major root damage during the relocation from nursery->container->ground.
      If severe, this can result in many years of struggle (sometimes plant death) as the plant tries to recover.
      Therefore, I go out of my way to avoid this potentially deadly situation (see article link below for more info)

      Not enough water:
      Not watering enough (esp in sandy soil) can also lead to leaf loss.

      Too much water:
      On the other hand, with too much moisture, the roots cant breath or absorb nutrients.
      If the soil is chronically wet, this can lead to fungal infection and potentially deadly root damage.

      Not enough sun:
      A sun starved plant will look leggy and may be lacking leaves.

      Gophers can obviously eat roots. If the eating is not complete, the plant can be left to struggle supporting the remaining leaves with less ability to get water to them. And gophers can be so sneaky that you may not easily see their holes.

      Infections (aphids, scale, etc) can suck a plant of its resources and it may not have the energy to make leaves.

      (A picture of your tree might help if you were able to post somewhere and provide the link).

      Hope this helps a bit.

  7. I’ve been having my nagami kumquat tree in a pot for the last 5 years. It has been fruitful year around. I have it positioned directly under a valley of my house so it gets plenty of water. I’d like to transplant it and put it in my yard. My soil is mostly clay. Should I do that or would it be a good idea.

    • Thomas Osborne, MD

      Hey Bruce
      Thanks for the great question.
      Very insightful of you to be asking about transplanting.

      A while back I wrote an article on the best way to transplant/plant (link provided below).

      That should cover almost everything for you.

      However, that article was written with the assumption that the tree is being transplanted from a nursery container. Therefore, three additional thoughts come to mind that you might face.

      1. Container type:
      If you have your tree in a clay pot (or other container), it may be more challenging to get the plant out of the container safely. Best advice is to go slow and try to keep the root ball intact as much as possible. I personally err on the side of sacrificing a container/pot for the health of the roots… but that is just me.

      2. Root bound:
      If you see roots swirling around the edge of the container, it is probably root bound. This happens to most plants that have been in the same container for a few years. Once the root ball is safely removed from the container and in place, try to gently unravel the roots that are coiled up on the outside. The idea is to get the roots pointing outward so they can get a strong footing.

      3. Acclimatize.
      If your tree is currently in a some shade, and you want to plant in full sun then you might want to play it safe. I would first gradually move the tree into the sun so it can adapt to the new conditions.

  8. Hey Thomas,
    Could you help an absolute gardening beginner? I have just bought a Kumquat tree in a pot. After reading your earlier posts I am convinced my tree had experienced some significant shock and I look for best ideas to speed up its recovery. I also wonder how old the tree might be.

    It is about 1.5 m high (measured together with a pot). The trunk is aprox. 3 cm in diameter.
    There were some deformed leaves and I cut them off (usually 2-3 at the pick of the stem, I also removed a few broken in transport – altogether about 10-15 cuts). Could be moths at one of the leafs, but I am not sure. I sprayed the plant well with water, inspected all the leaves, and positioned at my balcony (sunny, open). The weather is very hot these days (up to 32 C). And the soil came dry form the gardener, so I watered it well before night adding small dose of organic fertilizer. I repeated watering in the morning and again in the evening and probably overdone a bit. The soil is heavy and soaked, although no water shows up from the drainage holes.
    My concern started when I notices a few small leaves on the floor, which must have fallen today, and all the flowers and flower buds also gone (they were very few, sth like 5-8).

    What would you recommend to do since now on to ensure best chances for the poor tree?

    • Thomas Osborne, MD

      Thanks for the note.
      I will try to help anyway I can.

      Tree age:
      It is really difficult to accurately determine tree age by height alone.
      Conditions play a major role in tree growth. For example, you might have a young tall tree or a small old bonsai.
      If you have not planted the tree from seed then the other option is to cut the tree in half and count the rings.. but that kindof defeats the purpose.

      You mentioned moths on your tree.
      I would look into this further. There are various infections that can look like little moths and they need to be addressed. This infections can suck the life out of a plant. This could be related to the stressed condition of your plant. You also want to spray your citrus for leaf miner, this same spray will remove the other unwanted sap-sucking guests. Check out an article I wrote on the topic for more details.

      Other stress considerations:
      Growing in a container is difficult. The soil dries out fast, the soil temperature flux throughout the day is more intense. An automatic watering system can be a big help and save you a lot of hassle. Here is a Link to a complete patio type of watering kit on Amazon. http://amzn.to/1JnMyJH

      Fertilization is more difficult for container plants. I generally recommend organic fertilizer for potted citrus because it is more forgiving to use. Amazon has a bunch of options available (from reasonable http://amzn.to/1CHrhhk , to expensive http://amzn.to/1SsyOSV).

      Even if you do everything correct, a tree will eventually get root bound in a container-which will cause most all trees to decline significantly in health. Additionally, roots may plug up the drainage holes causing overly moist conditions. Furthermore, a potted tree can also topple over adding to the stress on the whole plant from the traumatic pact. Transplanting to a large container helps all of these issues.

      Hope this helps!

  9. Hi Tom,

    Many thanks for your rich and prompt answer. It helps a lot!

    In fact the deformed leaves have looked like those in the pictures by your leaf miner article. I did not see the white “trails”, but the rest is really very similar. Thus I will definitely search for some kind of spray available in Europe and matching your suggestions. The same applies to the fertilizer – on the list already.

    I will skip the automatic watering system, as I have no water supply at the balcony. I need to stay on the “manual”, but by now I know the soil in this pot holds the water more than any other of my few plants.

    I intended to move the tree to a bigger container anyway, but my question about this action are:
    – Should do it asap, or wait some time to let the tree take a break after already experienced stress?
    – Should I use similar soil as the one the tree has now (thick, dark, solid and holding water) and just ensure a 5-7 cm deep drainage at the bottom with keramzyt balls or stones, and sizable holes in the pot bottom?

    I hope I do not overuse you with the above new questions.

    • Thomas Osborne, MD

      Hey Katarina
      No problem, very happy to help.

      When to transplant:
      Good question. But not an easy one to answer.
      To some degree, it likely depends on the type of stress the plant it experiencing.
      If it is an acute stress (lack of water, bug infestation, traumatic injury), they it makes sense to wait a bit for the plant to recover.
      If it is a chronic problem (being root bound, poor container/soil) then you need to fix that environment for recovery sooner than later.

      Soil type:
      If you talk to someone who is really into soil science, they will tell you all kinds of nuanced details of different soil types… And many of those different soil types look the same to the average person.

      Soil for container citrus:
      Disclaimer: since I havent grown citrus in containers, I do not have direct experience. Perhaps another reader can add some wisdom. None the less, I do have some general ideas for you.

      For container general plants (not cacti), many people suggest a soil that holds moisture (with things like peat moss) bc the soil in containers tends to dry out fast.
      However, if you are planting in the ground, too much peat moss is not typically what you want your citrus roots to be growing in bc it may promote overly damp conditions.

      I have even heard of specific soil blends made just for potted citrus… However, I have not actually seen these alleged soils in stores.

      So if it was me…
      I would probably just get a soil blend made specifically for potted plants.
      But then again, I might just mix something up with what I have on hand.

      Hope this helps.


  10. Hi Tom,

    Thank you so much again.

    I guess I will observe the tree for some days and see. I would bet rather for the acute stress of the a bit harsh relocation and my inexperienced treatment. The garden center, where I bought the plant looked rather professional (so hopefully it was well treated there) and if there is a leaf-miner attack – I would not say it is massive.

    I will look for the special for citrus soil. Perhaps I will find it. I hope a better water balance will be a good start.

    Once more: great thanks for all your expert suggestions,

  11. Hi Dr Tom

    I live in Northern California with very hot summers so I planted my kumguat on the west side of the house but it gets shade during the hottest part of the day. It’s been in the ground about four months and appears to be doing well …new growth and had lots of flowers. However, after the flowers the little “nubs” left on branches, have started to dry up and drop off . Is the tree still in transplant shock from planting ? Or something else ? I think it’s getting the right amt of water ….but maybe to much ???

    Thank you for giving your time to stumped gardeners like me 🙂


    • Thomas Osborne, MD

      Hi Elaine
      Thanks for the note.

      Its hard to tell without a picture, but…
      When you say “nubs” do you mean the central part of the flower that is left behind after the petals fall off?

      If so.. then it sounds like the fruit might be aborting early. This is pretty common for a newly planted tree. Basically they are diverting energies to new roots and recovering from the move.

      Anyhow, if a tree does not do this on its own, I basically recommend that you do it. Pulling off off the fruit from young and/or newly planted trees will encourage the plant to spend its energy more responsibly during this critical establishment stage.

      Side thoughts:
      Too much water or too little water may result in many different plant symptoms.
      The following are some common considerations.
      Both too much and too little water may result in yellowing of the leaves. However, yellowing is more classically associated with too much water.
      Too little water often results in withered-droopy leaves and/or dropping of leaves.

      Hope this helps.


  12. Dr. Osborne,

    What causes Nagami fruits to be dry and mealy to the taste vs. juicy and crisp? Mine is a grafted plant cultivated on a container.

    Thank you for any answer you may offer.


    • Thomas Osborne, MD

      Hey Ron
      This is a great question.
      Citrus can become dry and pithy for a few reasons.
      (this may sometimes be referred to as “granulation”)

      Young trees that are not established enough, trees grown on vigorous rootstock, drought/water stress, and poor fertilization can all be causes or contributing factors.
      Even overripe fruit, and extended warm growing season has also been reported to be a cause.

      If your tree is young, this should get better over time.
      If not, then review the other causes and adjust to optimize.

      Hope this helps,

  13. I live in Northern California on the bay side of the San Francisco Peninsula and have a kumquat tree that had lived in a pot for several years. I planted it in the ground about 2 years ago. It loves it there, but has now reached the eaves of the adjacent porch and is bending for more space. I need to move it to give it more room. When should I do this?

    • Thomas Osborne, MD

      Hi Roberta
      Great question and good idea to move your Kumquat.

      Best time of year for citrus transplantation:
      In my experience, the best time to move citrus is when it is cool and wet… basically now (Winter/Fall).

      Additional steps to ensure transplantation success:

      I dont generally purne citrus unless they are growing in the way or have dead branches
      However, at transplantation I do prune a bit more than usual. I remove the branches that will be in the way during the transplantation process (mostly lower branches). I also remove any fruit and flowers. This will put less strain on the tree.

      Root ball:
      The bigger the root ball you can get the better.
      Putting some cloth (burlap/old sheets/etc) around the rootball when you are trying to move it will reduce damage to the roots (the tiny-microscopic hairs on the roots that do most of the work get sheared off with movement).
      This root cloth also makes it easier to move the tree.

      If you can transplant into a gopher cage that is great too.
      How to build a gopher cage

      Additional steps:
      Then water the heck out of the tree after transplantation.
      More info on my most effective method of planting via this link: Best planting technique: 7 important steps

      Best of luck,

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