Pictures of a kumquat tree

Kumquat Tree Care: Tips For Growing Kumquat Trees

Kumquat (Fortunella japonica syn. Citrus japonica), sometimes spelled cumquat or comquot, is a small citrus fruit that grows in climates too cool for other citrus plants. The fruit is sweet and tart at the same time and is eaten without removing the peel. If you are interested in trying your hand at growing kumquat trees, you should gather as much kumquat tree info as possible to avoid any kumquat tree problems later down the road.

Kumquat Tree Info

Kumquats grow on evergreen trees and are native to China. They reach heights of 8 to 15 feet and have a vase-like or rounded canopy. In spring you’ll be treated to showy, fragrant white flowers. The trees are self-fertile, so you’ll only need one to produce fruit.

Growing kumquat trees is easy. They need full sun and tolerate any soil pH and most soil types as long as the soil is well-drained. They also tolerate seaside conditions. Kumquat trees are suitable to USDA plant hardiness zones 9 and 10, and withstand winter temperatures as low as 18 F. (-8 C.)

Kumquat Tree Care

As part of your kumquat tree care, you should keep the soil moist around young trees, but not wet or soggy. Once the tree is established, water during dry spells.

Withhold fertilizer for the first two or three months. Use a fertilizer designed for citrus trees thereafter, following the label instructions.

Use a layer of mulch over the root zone to help the soil hold moisture and inhibit weeds that compete with the tree for moisture and nutrients. Pull the mulch back several inches from the trunk of the tree.

Kumquat trees don’t require pruning except to remove suckers that drain the tree’s resources. If you want to prune to shape the tree, do so after you harvest the fruit but before the flowers bloom in spring.

How to Care for Kumquat Trees in Containers

Kumquat trees don’t tolerate being root bound, so you will need a very large pot. Drill extra large drainage holes in the bottom of the pot, and cover the holes with window screen to keep the soil from falling through. Raise the pot off the ground to improve the drainage and air circulation.

Kumquat trees in containers need extra protection during freezing weather because of the exposed roots. Cover them with a blanket when frost threatens.

Kumquat Tree Problems

Kumquat trees are susceptible to root rot diseases. Avoid excess moisture and make sure the soil is well-drained before planting. Avoid piling mulch around the base of the tree.

Aphids and scale insects sometimes attack the tree. Natural predators usually keep these insects from becoming a serious problem. You can use insecticidal soaps as a contact insecticide and horticultural oils early in the season. Follow the insecticide labels exactly, and store unused portions in their original container and out of the reach of children.

Q: Last month I planted a Nagami kumquat tree from a 15 gallon pot. Now, all the other citrus trees in our garden are flowering but not the kumquat. Does it need special care to make it flower and fruit?

A: For those readers not familiar with kumquats, they are very small orange-colored fruits in the citrus family but not in the genus Citrus; they are in the genus Fortunella. There are several characteristics that distinguish kumquats. Most noticeable is that the flesh is sour, but the peel is sweet. Consequently, the entire fruit is usually eaten whole, either fresh or preserved.

For readers considering planting a kumquat tree, there are several varieties of kumquats that may be available at local nurseries. The most common variety is the Nagami, with its familiar oval one inch fruit. A seedless form of Nagami, marketed under the name Nordmann, may also be available. Nordmann fruits may grow to one inch wide by one and one-half inches long. Those who are especially fond of kumquats often seek out the Meiwa kumquat. It produces a round fruit that is up to one and one half inches in diameter. Meiwa had a thicker rind so it is regarded as a sweeter fruit than the Nagami. All varieties come is sizes suitable for planting in the ground or growing in pots.

Less obvious is the fact that the trees are exceptionally cold-tolerant and established trees can survive temperatures well below 20 degrees F. Kumquats can withstand these cold temperatures because they go somewhat dormant during the winter. Compared to other citrus trees, it takes them longer to initiate flowering when warmer weather arrives. You can expect your kumquat tree to begin flowering by summer and the next crop of fruit to be ready to eat in winter.

Kumquat trees don’t require any different care as other citrus trees, with one exception. Kumquat trees are especially susceptible to zinc deficiency. When the deficiency becomes acute, the leaves may become mottled yellow and green and are reduced in size. The condition is sometimes referred to a Little-leaf disease, although it is not a disease at all.

To prevent the deficiency, use a citrus fertilizer that contains zinc. In addition, each spring, apply a micronutrient supplement that contains iron, zinc, and manganese to the leaves of the tree. These supplements come in either liquid or powder form and are mixed with water before application. All citrus trees will benefit from this micronutrient application, not just kumquats.

Q: My azaleas have almost finished blooming. Is now a good time to prune them?

A: It is best to prune azaleas immediately after they have finished blooming. Cut back overly long stems to encourage new, more compact growth. Remove any crossing branches or dead wood. Follow this pruning with a high nitrogen fertilizer formulated for acid loving plants to stimulate new growth and prevent chlorosis. Once new growth has begun, use a fertilizer low in nitrogen monthly until fall. Your azaleas will then require no more fertilizer until the following spring.

Ottillia “Toots” Bier has been a master gardener since 1980. Send comments and questions to [email protected]

Kumquat tree growing shrub or tree of the genus Citrus also known as Cumquat, Kumquat tree grow as perennial evergreen plant with edible fruits also used as ornamental plant for the leaves and the fruits and can grow as dwarf or bonsai, It can grow in tropic, subtropical or mediterranean climate and growing in hardiness zone 8+.

Leaves color dark green in oval shape.

Flowers white with yellow stamen.

Kumquat fruit

Fruit taste sour with little bit bitter, fruit size ~1 -4 cm and color is orange, inner fruit divided by segments, the segment cover with soft thin layer, it containing the pulp (little cones covered with a thinner layer). Rind color orange, the edible part is especially the rind eaten raw, the taste is sweet and little bit bitter also used as flavor and fragrant

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Kumquat treeGrowing Kumquat treeKumquat tree flowerKumquat flowerKumquat fruitHarvest Kumquat fruit

How to grow Kumquat tree – grow and care:

How to care for kumquat tree:
Frost free, well drained, pruning once a year

What is the best way to start growing Cumquat plant:
Plant / Seed – explanation bellow / Cutting

Is it necessary to graft or use vegetative reproduction?
Yes, necessary

Difficulties/Problems with growing:
When the tree young very sensitive to citrus leaf miner, thorns

Planting season:
Spring to summer in hardiness zone 8-10a, spring or autumn hardiness zone 10b-11a, possible also in summer and winter the main problem it’s hot and cold days that might cause future problem and even kill the plant, hardiness zone 11b+ planted all year

Pests and diseases:
Citrus leaf miner, aphids, citrus foot rot, ant, citrus gummosis

Pruning season:
When there is no fruits on the branch

How to prune a kumquat tree:
Dead branch, cross branch, too much density

Size of the plant:
0.3-4 m (1-12 feet), possible to grow it as shrub 0.3-1 m (1-3 feet) or tree 1-4m (3-12 feet)

Growth speed in optimal condition:
Medium growing in perfect condition can grow fast

Irrigation water management requirement:
Small amount of water

Light conditions in optimal condition for growing:
Full Sun

Is it possible to grow indoor?
No, but commonly grow indoor as bonsai on the window

Growing is also possible in a planter /flowerpot / containers:
Yes, when grow in container need to make or take dwarf tree or bonsai, even bonsai can bear fruits, need to use potting soil or mix of peat soil with perlite, drainage and holes in the pot important, don’t let the water stand in the bottom of the pot, need ever few years to switch the soil of the pot and better to start with pot that will be 20% bigger than the roots ball and every time to change it with new soil, no point that the soil will stay in the pot for no reason just lose the viability

Blooming information

When does flowers bloom?
Summer / Autumn

General information about the flower
Flowers are white with yellow stamen

Thinning / Deadheading of Kumquat tree Blossom:
The first year should thinning the flowers

Pollination is done by:
Bees, self-pollination

Edible Fruits

When do kumquat trees bear fruit
Autumn / Winter / Spring rarely but possible to keep the fruits until spring

Pests or diseases in Cumquat fruit:
Citrus stubborn disease, citrus black spot, alternaria

What can be done with big quantities of Kumquat fruit?
Eat, juice, the rind used fragrant, fruit leather, sugary rind

Work requirements on the fruit:
Pick up (sometimes cut brunches that grow into the fruit)

How long does it take for a kumquat tree to bear fruit?
1-3 years

Ripening of fruit
Possible to pick up the fruit before and let them ripening them in the house

How to grow a kumquat tree from seed

Sowing requirement:
Moist soil, hot weather, sunny location

Saving seeds until sowing:
Dry, dark location in room temperature

Sowing season:
Spring (possible in the autumn in hardiness zone 10b+)

Planting spacing:
Better in separate pots

Depth of Sowing:
2cm (1inches)

Conditions for seeds germinate:
Don’t let it dry, rich soil and sunny location

Watering requires for Seeds:
Average amount of water

Germination time:
2-4 weeks

Condition of seedling:
If there is Citrus leaf miner in one of the trees in the area better to put it in greenhouse or indoor

Scientific name:

Citrus japonica

Alternative names: Cumquat, citrus kumquat

Blooming Seasons

  • Autumn flowers
  • Summer flowers

Edible Parts

  • Edible Fruit

Culinary Uses

  • Alcoholic beverages
  • Beverage
  • Dried fruit
  • Eaten raw
  • Fruit
  • Ice pop & Ice cream plants
  • Juice

Flower Colors

  • White flower


  • Mediterranean Climate
  • Subtropics Climate
  • Tropics Climate

Harvest season

  • Autumn Harvest
  • Winter harvest

Ornamental parts

  • Ornamental fruit
  • Ornamental leaves
  • Ornamental plant

Plant growing speed

  • Average growing plants

Plant life-form

  • Evergreen
  • Perennial plant
  • Tree

Plant uses

  • Edible plants
  • Ornamental plants

Planting season

  • Autumn Planting
  • Spring Planting
  • Summer planting

Plants sun exposure

  • Full sun Plants

Watering plants

  • Regularly water
  • Small amounts of water

Hardiness zone

  • Hardiness zone 10
  • Hardiness zone 11
  • Hardiness zone 12
  • Hardiness zone 13

How to Plant a Kumquat Tree

Kumquat trees are the most cold-hardy of the citrus family. Some varieties can endure temperatures down to 10 degrees F, but they do require a hot summer. Believed to have originated in China, the kumquat tree is generally grown in Florida, California and Texas. The kumquat tree provides a fruit that can be eaten raw or preserved in sugar syrup. It is a shrubby, slow-growing tree that is 8 to 15 feet tall. The most common kumquat species with edible fruits are Meiwa, Hong Kong, Nagami and Marumi. The fruit is usually harvested in January. In USDA Zones 8 to 11, kumquat trees can grow outdoors in the ground. If you live in Zones 4 to 11, kumquat trees need to be grown in a pot as a patio plant and moved indoors during the cold winter months. Because kumquat trees are drought-tolerant and pest-resistant, they are rather easy to plant and grow.

Planting in the Ground Outdoors

Plant your healthy, young kumquat tree in the ground if you live in Zones 8 to 11. Add Mycorrhizal fungi to the soil at the time of planting to enable your kumquat tree to access more of the nutrients in the soil and to maximize fruit production.

Place some iron tablets in the ground around the tree if your soil’s pH level is greater than 7.0. This will prevent iron deficiency.

Plant your kumquat trees in full or partial sun, approximately 8 to 10 feet apart. Kumquat trees will adapt to many different well-drained soils. The Nagami kumquat does well in sandy soils, however.

Keep the ground clear of weeds about 3 feet around the tree.

Planting in a Container

Plant your kumquat tree in a container if you live in Zones 4 to 11. Use a sand-based potting mix. Make sure you use a large enough container to give your kumquat tree room to grow and a container that has adequate drainage holes.

Put a layer of gravel on the bottom of the container to help provide good drainage. Allow the top 1-inch of soil to dry before watering your tree and avoid over-watering.

Place the container in bright sunlight, preferably in a window with southern exposure. You can place your kumquat tree outdoors in a sunny spot during the warmer summer months.

Kumquat tree, also known as Citrus japonica, is an easy-to-grow fruit tree. From all the citrus trees, this one is the most beautiful with dark-green, glossy leaves. It’s known for its bright orange fruits, which are deliciously tart and sweet.

These trees, native to eastern Asia, are small and beautiful. If you’re looking to grow them in your backyard or near a window, then keep reading.

Quick Care

Massive harvest of kumquat fruits from a small section of one tree.

Common Name(s) Kumquat, nagami kumquat
Scientific Name Citrus japonica
Germination Time 2-4 weeks
Days to Harvest ~90 days for fruits to form
Light Full sun
Water: Medium
Soil Sandy loam slight clay
Fertilizer Frequent
Pests Citrus pests, mealybug, aphids
Diseases Armillaria root rot, anthracnose, citrus blast

Kumquat plants have thornless branches and extremely glossy leaves. They bear dainty white flowers that occur in clusters or individually inside the leaf axils. The plants can reach a height of up to 8 feet and grow 6 feet wide. They bear yellowish-orange fruits that are oval or round in shape. The fruits can be 1″ in diameter and have a sweet, pulpy skin and slightly acidic inner pulp.

Despite being citrus trees, the flowering season of kumquats arrives much later. Kumquat tree flowers in late spring into early summer. It is an easy-to-care, cold-hardy plant that can tolerate temperatures as low as 18°F (-7°C).

Kumquat Varieties

Botanically, many of the varieties of kumquats are classified as their own species, rather than a cultivar:

  • Nagami: The most popular variety, also known as oval kumquat.
  • Meiwa: Large round kumquat, a hybrid of ‘Nagami’ and ‘Marumi’.
  • Marumi: Round kumquat, a bit spicier in flavor than ‘Nagami’.
  • Hong Kong: A native version, often growing in hilly or mountain regions of China.

Whichever you choose, kumquat trees produce fruit that is are round, oval-shaped, and bell-shaped. Nagami kumquats, which are the most popular, have oblong, juicy fruits, which can be eaten whole or used to make marmalades.

All the kumquat trees are self-pollinating, so you only need to grow one tree. The plants require moist soil, so they need ample water to prevent drying of roots. Kumquats can tolerate both frigid and hot temperatures.

Planting a Kumquat Tree

Growing a kumquat tree is very easy. Here’s a breakdown of when, where, and how to plant this attractive evergreen tree.

When to Plant

You can successfully start a new kumquat plant by planting the seed in spring. Spring is the ideal time for kumquats as the temperature is pleasant with higher chances of rain and, of course, lots of sunshine.

Where to Plant

Plant in a place where there’s full sun. Although they’re good with any type of soil, they mainly do well in seaside conditions. You can still plant them in your backyard or outside on your patio as long as they get well-drained soil. They also do well in pots or containers with suitable drainage holes.

How to Plant

It’s better to purchase a kumquat tree from a local nursery. Kumquat can sprout from seed, but the plant is mostly weak. Choose a sunny spot and plant the tree in spring to ensure that the kumquat is well-established before winter arrives.

After choosing the spot, dig a hole at least 3-5 times wider than the root ball. Carefully place the tree into the hall and ensure that the soil is level with the ground. Tap down the soil for a smooth layer.

Since kumquats need regular hydration, water the plant thoroughly and don’t let the soil become dry. Mist often, at least a few times a week, until the tree establishes.

Add organic mulch to the surrounding area, about 2-3 inches, while keeping the mulch at least 10 inches from the trunk.

Ensure proper watering and soil conditions for about a month and then fertilize. You can use a high-quality citrus formula.

A kumquat tree full of fruit I harvested from this past summer.

Kumquat tree, famously known as nagami kumquat, is relatively easy to grow. However, like other citrus trees, it can’t survive on neglect. When you’re planting the tree, it’s essential to treat it with a lot of care. The journey is extremely rewarding once the kumquat tree begins to bear delicious citrus fruit. Here’s a breakdown of how to nurture and look after it.

Sun and Temperature

As aforementioned, kumquats are best grown in full sun. They need at least 6-7 hours of sunlight every day for healthy root development. If you’re growing them indoors, make sure to keep them near a window for maximum sunlight. Kumquats do well in USDA hardy zones 9 and 10 and can survive in temperatures as low as 18 degrees F (-7 degrees C). If temperatures drop lower, bring them inside.


The key to growing any citrus fruit tree is proper watering. If you’re growing kumquats in pots, the soil needs to be moist but not wet. For this, you must ensure the container has suitable drainage holes.

Kumquats need regular watering, especially when the plants are young. However, make sure not to overdo it. To check for hydration, stick your finger at least 3-4 inches in the soil; if you feel dampness, wait until the soil dries out a little to water again. However, if you see a sign of dryness, water the plants until it begins to run out from the bottom of the pot. You can also light mist to avoid excess water.


Kumquat tree survives well in almost any soil pH. But when growing it, use high-quality potting soil to enrich them. You can also add a layer of gravel or pebbles for proper drainage.


Apart from the cold winter months, kumquat plants need regular fertilizer. In spring, feed the plant with an all-purpose, slow-release citrus fertilizer. As the plant grows, give it diluted liquid fertilizer, like fish emulsion or liquid kelp, regularly. Always water before and after the application to prevent leaves from burning.


Kumquat tree doesn’t require much pruning except when you have to remove dead or wilting branches that may be sucking up the tree’s resources. If you want to shape the tree, make sure to do so before the flowering season in spring and after harvesting the fruit.

Propagating Kumquat Trees

The trees aren’t generally grown from seeds. You can propagate them by grafting them onto the rootstocks of grapefruits and oranges.


When growing kumquat trees in containers repot every 2-3 years in containers that are at least a few inches bigger than the previous one. The ideal time for repotting is during the leaf-growing stage in spring.

Harvesting and Storing

Here’s how you should harvest and store the fruit from kumquat trees.


The harvesting time for most varieties begins from November through January, while for others, it’s from December to April. The fruit is ripe when it’s slightly soft and deep orange. Pick the fruit using scissors to avoid damaging the plant. You can also trim the fruit along with a small piece of the branch.


Kumquat fruits don’t have a long shelf life because they have thin, delicate peels. If you want to store them for a week or so, keep them in fully covered paper bags or plastic bags at room temperature. However, it’s best to store the fruit in the fridge.


Even when kumquat trees require lots of care, gardeners don’t face many growing problems.

The trees are susceptible to root rot diseases if the soil isn’t well-drained. The best way to avoid this is to ensure proper drainage and only water when needed.


Kumquat trees are susceptible to mealybug infestations, citrus pests, and aphids. Keep the soil well-drained and avoid excess moisture and piling too much mulch around the tree. A good insecticidal soap or a robust horticultural oil will help combat the infestation.


Root rot, citrus blast, and anthracnose are other common diseases. If you see any sign of root rot, it’s best to remove the affected branch. To prevent citrus blast, protect the trees from strong winds and follow by cutting off any diseased twigs and dead branches.


Q. Where do kumquats grow in the USA?

Kumquat trees are most often grown in Florida and California.

Q. What are the benefits of eating kumquat fruits?

Kumquat fruits are incredibly high in vitamin C and fiber. Eating them can help strengthen the immune system and support weight loss.

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Clarisa Teodoro
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Fortunella crassifolia Swingle

CRC 1471

PI 539721

Photos by David Karp and Toni Siebert, CVC. Photo rights.

Source: Received as a live tree from W.T. Swingle, USDA, 1924.

Parentage/origins: Parents unknown.

Rootstocks of accession: Carrizo citrange, Cleopatra mandarin

Season of ripeness at Riverside: Year-round

Season of flowering at Riverside: May to September

Notes and observations:

Meiwa kumquat, Fortunella crassifolia, is a lesser-known species of kumquat.The tree is similar to the Nagami kumquat in appearance, but it cannot be budded onto all the same rootstocks as Nagami. Trifoliate seems to be the best rootstock choice for Meiwa. Kumquat trees are especially susceptible to zinc deficiency, which can cause small leaves and reduced internode distance. As with Nagami, Meiwa trees are semi-dormant in winter, allowing them to withstand temperatures below freezing. The flowering season is in summer, and the fruits mature in late winter. The almost-round fruits are orange at maturity, up to one and one-half inches in diameter. The sweet rind is thicker than the rind of Nagami, making it seem sweeter than Nagami. The flesh is light orange, contains a few seeds, and is acidic.

Description from The Citrus Industry Vol. 1 (1967):

“This species is the Ninpo, Meiwa or Neiha kinkan of Japan. The most distinctive features of this kumquat are the short oblong to round form and relatively large size of the fruit, the more numerous sections (commonly seven), the very thick and sweet rind and comparatively sweet flavor, and the low seed content (many fruits are seedless).
While Swingle originally (1915) considered it to be a valid species, he later concluded that this variety is a natural hybrid between the oval and round kumquats.
It is much the best variety for eating fresh and is reported to be widely grown in Chekiang Province of China and to some extent in Fukuoka Prefecture of Japan. Meiwa is said to be slightly less cold-hardy than Nagami but is increasing in popularity in the United States.
Tanaka reports the existence in Japan of a variegated form with striped fruits, which is a most attractive ornamental.”

Availability: Not commercially available in California. This accession does not have an approved budsource. Please refer to the CCPP for information on another approved budsource (performance should be similar) or to start an introduction inquiry.

USDA Germplasm Resources Information Network page for Meiwa kumquat (CRC 1471)

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Trifoliata – This rootstock is grown from seed sourced from Australia or USA. The seeds are harvested from a particular type of sour orange which produces many seeds inside the fruit. Trifoliata is the standard rootstock for citrus trees with excellent hardiness to difficult soil conditions, to cold soil temperatures, with good vigour and heavy crops. Rootstock growth (‘suckers’) that sprouts from below the bud union (about 15cm from ground level) will look different to the variety growth with distinctive small tri-lobed leaves and many sharp spikes – this growth should be cleanly snipped off. Trees on Trifoliata rootstock will grow to 3-4m tall.

Flying Dragon – A dwarfing rootstock for citrus trees, with trees on Flying Dragon growing to only 2m tall. Trees on Flying Dragon are best planted in warmer areas of the garden as the rootstock is not very cold tolerant. Another benefit of this rootstock is that the fruit is produced at an earlier age compared to trees on Trifoliata rootstock.Rootstock growth (‘suckers’) that sprouts from below the bud union (about 15cm from ground level) will look different to the variety growth with distinctive small tri-lobed leaves and many sharp spikes – this growth should be cleanly snipped off. This rootstock is grown from seed sourced from Australia or USA. The seeds are harvested from a particular variety of sour orange which produces many seeds inside the fruit.

Please note not all rootstock and variety combinations are available every year.

Growing Kumquats- The Pop-in-Your-Mouth Fruit

By Laurelynn Martin and Byron Martin

Kumquat ‘Nordmann
Seedless Nagami’
(Fortunella margarita)

Nagami Kumquat
(Fortunella margarita)

(Fortunella crassifolia)

Changshou Kumquat
(Fortunella obovata ‘Fukushu’)

The Kumquat is thought to have originated in Southern Japan and China. It was originally known as the “gam kwat” with an early reference in the 12th century. Kumquats are loved for their oval, oblong or round tiny fruit that produce abundantly on small trees in the ground or in containers. The bite-size, pop-in-your-mouth fruit have edible skin. Some varieties are sweet on the outside and tart on the inside; others are sweet all the way through. In 1864, Robert Fortune, a collector from the London Horticultural Society introduced kumquats to Europe, and shortly thereafter to North America. In 1915, Kumquats were no longer classified as Citrus japonica but were named after Mr. Fortune and the new genus became Fortunella.

Logee’s Kumquats
At Logee’s, we grow four varieties of kumquats. We grow them as grafted plants rather than cuttings because they don’t root readily and grafting the named variety onto an understock increases vigor and encourages early fruiting. We typically use Citrumelo or C. macrophylla as the rootstock.

‘Nagami’ (Fortunella margarita) This kumquat is often found in produce sections of your grocery store. The fruit is small and oblong and is typically more sour than the other varieties.

‘Nordmann Seedless Nagami’ (Fortunella margarita) The teardrop shaped fruit is tart and juicy and completely seedless. The fruit ripens from December to June.

‘Meiwa’ (Fortunella crassifolia) is the sweetest kumquat that we grow and it is sweet and delicious inside and out. It has a small round shape.

‘Changshou’ (Fortunella obovata ‘Fukushu’) is slightly larger than the other kumquats and also has sweet skin with a sweet inner flesh. The Changshou bears fruit heavily and can produce fruit twice a year.

Fortunella hindsii is another ornamental kumquat that makes an excellent bonsai. The fruit, although edible, is small and pea sized and has mostly seed and skin. Logee’s doesn’t grow this variety.

Growing Kumquats

Light Requirements
Full to partial sun is required for growing kumquats. The more light the better but as with all citrus, they can be grown indoors on an east or west-facing window and flower and produce fruit.

The flowering cycle for kumquats is later than most citrus. They flower in late spring into early summer with the Changshou often flowering twice a year, making it an almost ever-bearing plant. The sweetly fragrant blossoms are followed by fruit that ripens in mid-winter for us with the fruit holding onto the trees well into late spring. They bear a heavy crop at a young age making them excellent specimens for a container fruit garden.

Soil/Hardiness Zone
Kumquats are well adapted to most well-drained potting mixes. We grow them in a standard soilless mix that has a pH around 6. For outdoor growing, kumquat plants are cold hardy to Zone 8b and upper 9 and are known to be some of the more cold tolerant citrus. The Changshou is thought to be more cold sensitive than the other species.

Moderate amounts of fertilizer are needed during the active growing season. Reduce and restrict fertilizer when going into the winter season. There are several excellent citrus fertilizers on the market but any organic balanced fertilizer will work. We like to top dress the soil, because it slowly releases fertilizer to the plant over a period of time.

When the kumquat plant is young, pinch back the growing tips and shoots to make the plant full and bushy. This encourages a sturdy well-branched structure so it can carry the future fruiting load. Keep in mind that kumquats bear so heavy that they can bend the limbs to the point of breaking on young plants. Older plants need to be pruned periodically to maintain shape and this is best done after fruiting. On mature plants, it’s best to selectively prune top branches that are too tall or reaching out but leave the inner and side growth so you don’t lose next year’s fruit. A branch or lead that is cut in late spring or early summer generally won’t flower until the following year.

Pest/Disease Problems
Scale, spider mite and mealy bug can be problems on citrus. Attention needs to be given when moving plants indoors in late summer or early fall. A preventative spraying of neem oil twice in one-week intervals will do wonders to keep the kumquat tree clean throughout the winter. This is especially true if scale and mealybug have been a problem in the past. Spider mites often come in with plants that have summered outside and are not visible until the dry atmosphere of the winter home causes populations to explode. Root disease is only a problem if the plant is kept too wet and grown in cold damp conditions. We recommend growing in a clay pot and erring on the dry side when watering. Also, if you have a grafted plant that has been grown on a disease resistant understock, then root disease becomes less of a problem.

Special Requirements for grafted plants
Remember when grafted kumquat plants are young, shoots can develop below the graft union on the rootstock. These shoots need to be removed, otherwise they will dominate the plant and the grafted kumquat variety will stay small and barely grow. As plants get older, this rootstock suckering slows down or stops.

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Caring for Grafted Plants-Article


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