Kumquats, or cumquats in Australian English, are a group of small fruit-bearing trees in the flowering plant family Rutaceae. Their taxonomy is disputed. They were previously classified as forming the now-historical genus Fortunella or placed within Citrus, sensu lato. Different classifications have alternatively assigned them to anywhere from a single species, C. japonica, to numerous species representing each cultivar. Recent genomic analysis would define three pure species, Citrus hindsii, C. margarita and C. crassifolia, with C. x japonica being a hybrid of the last two. The kumquat plant is native to Southern China.
Kumquat plants have thornless branches and extremely glossy leaves. They bear dainty white flowers that occur in clusters or individually inside the leaf axils. 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). The edible fruit closely resembles the orange (Citrus sinensis) in color and shape but is much smaller, being approximately the size of a large olive.
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6 - 16 feet
5 - 10 feet
6.0 - 7.0
Growth Nutrition of Kumquat Tree
Fertilize the Kumquat tree with a suggested formula for use on citrus trees (complete fertilizers like 10-10-10, 8-8-8, etc.). Fertilizer is essential as soil may not be able to provide all essential nutrients to the tree. Kumquat trees need proper nutrients to grow roots, leaves, flowers, and fruits.
For kumquat and mostly citrus trees, the most important nutrients are nitrogen, magnesium, potassium and phosphorus and other nutrients are boron, zinc, copper and iron.
Types of Kumquats
Hong kong Kumquat
The Hong Kong kumquat (Citrus hindsii or Fortunella hindsii) is distinct from other kumquat varieties. It is usually grown for ornamental purposes. Its fruit is bitter, acidic, has little pulp with large seeds, and only grows to the size of a pea.
The Hong Kong kumquat is usually believed to be the closest living relative to the evolutionary ancestor of all citruses. It is the most primitive citrus plant and is often found growing wild throughout Southern China.
The Nagami kumquat produces small oval-shaped citrus fruit which can stay on the tree for an extended period of time. This adds to the attractiveness of the tree and its ornamental appeal. The tree can grow 6.5-16.5 ft (2-5 meters) though it can be pruned to remain a smaller tree at 6.5 ft (2 meters).
These round kumquats are also called Morgani kumquat of the citrus japonica family. Marumi kumquat trees produce edible golden-yellow fruit that are round and small. The skin or peels of these kumquat varieties tastes sweet, but sour at the center.
You can eat these types raw and fresh to experience its pulp tart-sweet taste, or process them into jellies, jams, and marmalades. But aside from being a staple fruit, marumi kumquats symbolizes good luck in some Asian countries, like China. Also, these kumquat types have a higher cold resistance, making them a popular type of kumquat tree to be planted in countries with colder climates.
Meiwa kumquat cultivars originate in China, but it has been introduced to Japan during the 19th century. The meiwa kumquat tree produces average-sized fruits that are round in shape. The rinds of the meiwa are thick with an aromatic peel that are high in volatile oils.
Meiwa also contain a lot of seeds that would produce a slightly bitter taste when eaten. But the peels of Meiwa is very sweet and should remove the bitter taste of those seeds.
These varieties of kumquats are from the basic types of Citrus obovata or Fortunella obovata family. It is also called fukushu kumquat and the kumquat trees of these types bear an edible round or teardrop shape fruit. These types are bright orange in color when matured or ripe.
The kumquat plant of jiangsu has distinctive leaves when placed beside other types of kumquats. These kumquats are usually planted as an ornamental plant, but they are also cultivated due to its edible fruit. Jiangsu kumquats are also eaten with its sweet peels to balance the tart flavor of its pulp.
These types of kumquats are from the kumquat hybrids of Fortunella polyandra or Tanaka’s Fortunella swinglei. This variety of kumquat is grown in the Malaysian peninsula and it is called limau pagar or hedge lime.
The kumquat tree of the malayan kumquats bear small and round citrus. It has a thin, smooth rind that’s divided into five parts or segments. You can find the seeds in its center that are oval in shape. Malayan kumquats taste sweet on its peels, with a protruding sour and tangy pulps.
The Indio mandarinquat (Citrus unshiu x japonica) is a cross between mandarins and kumquats. Mandarinquats are considered citrofortunellas and are commonly called orangequats. This variety originated as an open-pollinated seedling from a Nagami kumquat and an unknown plant.
They produce small, rounded orange fruits that are a bit bigger than kumquats. The shrubs stay small to medium in size with long, narrow, dark green leaves. Fruits are produced through many of the colder months of the year. Since it was not bred to be seedless, the fruit does produce a number of large seeds. Fruits are usually eaten whole and have tart flesh with a sweet skin.
Calamondin is said to be a kumquat hybrid by combining calamansi (Philippine Lemon) and mandarin orange. This is a very popular kumquat fruit found in the islands of the Philippines, but it is also believed that this kumquat originates in China.
Calamondin kumquats are very small, round shaped fruits that have an orange peel when fully matured. This natural hybrid fruit has a very juicy pulp that offers a sour tangy flavor.
Due to its hardiness and tolerance to low temperatures, calamondin kumquats are available whole-year round. Though, these citrus japonica fruits should be harvested when they are only half-ripe and just starting to change their peels color.
Eustis limequats are created by combining the Mexican Key Lime (west indian lime) and kumquat. This hybrid is definitely a good type to cultivate as it produces fruits with a strong and fragrant tart lime flavor, combined with the sweet edible peel.
The kumquat trees of eustis limequats produce a small, oval, greenish-yellow fruit that contains seeds or pips at the center of its pulps. The fruits can also be eaten as whole or make use of them to enhance the flavor of your drinks and dishes.
The Centennial Variegated kumquat is a commercial variety of the Hong Kong kumquat that is growing in popularity. The fruit is diploid, rather than tetraploid as in the wild. It is also popularly known as Golden Bean kumquat.
These produce fruit that is slightly larger than wild varieties. It is known for its striking variegated skin, which alternates green and yellow stripes before ripening to orange. This cultivar originated as a spontaneous genetic mutation, probably a cross between the mandarin and Nagami kumquat.
Nordmann Seedless Kumquat
The Nordmann Seedless Kumquat, as the name implies, is a type of kumquat that has been bred to have no seeds. This makes it ideal for eating fresh, with sweetly tart fruit under a thin, sweet skin. This variety is also widely used as an ornamental tree and can be grown in a container.
It blooms with fragrant blossoms in the summer, with clusters of bright orange fruit following in the cooler months.
When to Plant
The best time to plant or transplant a kumquat tree is in the spring after the threat of frost has passed.
Selecting a Planting Site
Choose a spot that gets lots of sun and has good soil drainage. Make sure no nearby taller trees will shade out the kumquat, as this can affect its growth and fruit production. The spot also should be protected from strong winds. If you don’t have an adequate garden site, container growth is a good option. Kumquats also can be grown indoors with enough light.
Spacing, Depth, and Support
Kumquats are typically planted as young nursery trees. Be sure to give a kumquat tree at least 5 to 6 feet of space when planting. The hole for it should be three to five times wider than the root ball and roughly the same depth as the root ball. A support structure typically won’t be necessary.
How to Grow Kumquats in Pots
Kumquats grow beautifully in containers, whether you choose a plastic, wood, clay, or stone planter. It's a great option if your climate isn't warm enough to plant a kumquat tree in the garden. Use the largest container possible (at least 5 gallons), and be sure that it has good drainage. If you're concerned about soil escaping out of large drainage holes, you can cover the holes with screening. Keep the container raised for good air circulation, being careful not to block the drainage holes.
Kumquat trees need full sun; they do best with at least six to eight hours of direct sunlight on most days. When grown indoors, place your tree by your brightest window or set it under grow lights. A kumquat will survive in bright, indirect sun, but it won't be as productive.
Kumquat trees prefer loamy, moist, well-draining soils with a slightly acidic to neutral soil pH. Don't plant them in heavy clay soils, as this can cause root rot.
These fruit trees like evenly moist but not soggy soil. If you stick your finger in the soil down to the second knuckle and it feels dry at your fingertip, it's likely time to water. A 2- to 3-inch layer of mulch over the tree's root zone can help to maintain soil moisture. Just make sure to keep the mulch at least 3 inches away from the tree trunk, because moisture retention on the trunk can cause diseases and decay and can provide a path for insect and rodent damage.
Temperature and Humidity
Kumquats don't like cold weather, though they can survive temperatures down to 18 degrees Fahrenheit. Ideal humidity levels are 50 to 60 percent. If your tree is indoors during winter when the heat is on and air is dry, use a humidifier or set the container on a tray filled with pebbles and water to raise humidity levels.
Wait two to three months after planting a kumquat tree before fertilizing. Then, use a citrus fertilizer following label instructions. Don't fertilize in the winter.
Kumquats are self-pollinating, which means they don't rely on insects to pollinate them and can fruit on their own.
Kumquat trees are heavy fruiters, with some varieties flowering and producing fruit twice per year. New starts or grafts might need two or more years of growth before they're ready for reliable fruiting. Buying larger trees might produce fruit in the first year.
The various cultivars can have different harvesting times. Some produce fruits from November to January while others from December to April. Kumquats are ripe when their skin is a deep orange color and the fruit is slightly soft to the touch. Use a knife or scissors to cut off the fruit, so you don’t risk damaging the plant by pulling off a larger piece than intended. The fruit can be used raw or cooked. It will store at room temperature for a few days or in the refrigerator for up to two weeks.
Pruning and Propagating Kumquats
Cut away any suckers sprouting below the graft bud, as they won't produce fruit. When the tree is very small, pinching off the tips of the shoots will encourage it to branch out. If you want to prune the tree for shaping, do this after the fruit has been harvested but before flowers appear the following spring.
Kumquat trees are produced by grafting fruit-bearing branches onto the rootstock of oranges and grapefruits. If seeds are planted, they won't produce viable trees. Most gardeners choose to purchase grafted trees from nurseries rather than trying the technique themselves, as it can be fairly complicated.
Potting and Repotting Kumquats
A potting mix designed for cactus or citrus plants is ideal for potting kumquats, but any general-purpose potting mix will suffice. Plan to repot your kumquat every two to three years into a container that is slightly larger than the original. These plants do not like to be rootbound. The best time to repot is the beginning of spring when leaves are emerging.
Just like other citrus trees, kumquats are not winter-hardy – meaning they are not well-adapted to survive our chilly winter weather. However, kumquats do need a cool indoor spot to rest in during the dormant period. A bright and cool place where the temperature lies between just above 0°C and 10°C, such as a garage that receives a lot of light, or an unheated conservatory or hallway, is therefore ideal for overwintering. You can find more plants for conservatories here. As a general rule, the warmer the place, the brighter it should be. If the kumquat is placed inside a room that is too dark or too damp, there is a risk of leaf loss.
Water your kumquat very sparingly during the winter – only water it when the surface of the soil has dried out
Fertilise your plant regularly with organic fertiliser during the summer months
Do not fertilise your kumquat during the winter and reduce watering considerably
Prune in February if necessary
Overwinter in a bright spot between 1°C and 10°C
Pests and Plant Diseases
Kumquat trees are susceptible to mealybug infestations, leaf miners, citrus scale, 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 or neem oil will help combat the infestation.
Anthracnose is a common citrus disease. This leaf spot disease can be prevented by spraying the tree three times annually with horticultural oil. If it appears, most copper-based fungicides will clear it up. You may also encounter alternaria leaf spots, and those should be handled similarly to anthracnose.
Citrus blast is a bacterial infection that spreads in parts of the US after wind-driven rain. The bacteria, Pseudomonas syringae, enters into the plant via points of damage from the wind. It causes withering of leaves and can lead to complete death of the plant. Plant your citrus trees with protection from wind, and use a copper-based fungicide to kill off bacteria.
Phytophthora root rot is another issue that may appear. This is usually a fungally-based root rot that is caused by overly-soggy soil conditions. Do not overwater your trees, and you should not encounter this problem.
Benefits of Kumquats
This tiny fruit has many powerful antioxidants that help fight off various critical health conditions like heart diseases, cancer, diabetes, etc. Kumquats is also a zero GI fruit that helps in diabetes management. It also contains zero to low fat which is also important for weight management. Let’s read about various health benefits of Kumquat:
Good For Heart Health
Nutrients in Kumquat like Vitamin C, fiber, antioxidants, and vitamin A collectively reduce the fat accumulation in the arteries and reduce the risk of blockages. Therefore, it mitigates the possibility of heart failure, stroke, and high blood pressure conditions. Eventually, it strengthens heart health. It also reduces LDL which prevents heart conditions.
Good For Digestion
It is filled with insoluble fiber as dietary fiber that allows good digestion. It removes conditions like constipation, disturbed bowel movements, gastrointestinal problems, and gastritis. In addition, it promotes gut bacteria to grow which encourages a good and strong digestive system.
Helps In Diabetes Management
Kumquat fruit has zero GI and low sugar content which makes it a superfood for diabetic people. It does not increase blood sugar levels after consumption. Its dietary fiber also slows the digestion & absorption of sugar from food which helps in diabetes management.
Helps In Weight-Management
A high-fiber fruit is always gold for people who aspire to lose weight. Dietary fiber in Kumquat food slows digestion and keeps a person feeling full for a longer time. It reduces unnecessary munching, which is the reason for weight gain. Apart from this, kumquat fruit also contains poncirin flavonoid which is associated with reducing obesity.
Kumquat is rich in powerful antioxidants that kill free radicals in the body. The formation of free radicals is associated with the development of cancerous cells. This citrus fruit also contains apigenin flavonoid that reduces the risks of cancer.
Good For Skin Health
Vitamin C is one of the major contributors to skin health and Kumquat is a rich source of Vitamin C. It increases collagen formation that gives firm, radiant, wrinkle-free, and healthy skin. Antioxidants like vitamin C also kill free radicals that cause aging effects on the skin like fine lines and wrinkles. This protects the skin from aging.
Good For Eye Health
Vitamin A plays a major role in good eye health. Kumquat fruit is rich in vitamin A, and beta carotene that promotes eye health. Carotenoids help in improving eyesight and also help in controlling night blindness.
Citrus fruits promote good immunity because of the presence of vitamin C, a powerful antioxidant. Other antioxidants like flavonoids also strengthen immunity. Apart from antioxidants, Kumquats have antibacterial, antimicrobial, and anti-inflammatory properties that fight off various infections and fevers. Therefore, it makes you strong and boosts your immunity.
Yes! Kumquats can also improve mood swings, and reduce stress, anxiety, and depression. Its Vitamin C plays a vivid role in enhancing mental health.
Good For Bone Health
A good skeleton system requires an adequate amount of calcium which is found in Kumquat. It meets 6% of our daily calcium requirement and increases bone density. It also prevents fractures and low bone density.
Do you know that Kumquat helps in breaking gallbladder stones? Gall bladder stones are painful and induce inflammation. This tiny fruit is helpful to reduce these painful gallstones because of limonene, a compound found in it.
1. Add Kumquats to a Salad
Kumquats' sunny citrus taste will wake up your taste buds when you add them to a salad. They are the perfect balance for bitter greens such as radicchio or the licorice tasting fennel.
2. Turn Them Into Kumquat Jam or Marmalade
As a citrus fruit, kumquats are perfect for turning into jam or marmalade. A bonus is you don't have to peel and section them. Spread on bread or biscuits as part of a delightful breakfast.
3. Bake Kumquats in a Cake
Just like apples, berries, and other fruits, kumquats have their rightful place in a cake. Try an easy and moist kumquat ginger cake for a bright and beautiful cake you can enjoy with milk, tea, or coffee.
4. Roast Kumquats
Yes, you can actually roast kumquats in your oven. Cut them in half, toss them with a little bit of honey, and then roast on a parchment sheet-covered baking pan for a half hour at 325 degrees.
What can you do with roasted kumquats? They make a sweet side dish for chicken, duck, and pork.
5. Add Kumquats to Beverages
You can slice kumquats in half and add them to your favorite sweet cocktail, or even add a spoonful of kumquat marmalade to your drink. Or you can blend them whole with other citrus juices to make a kumquat puree.
Like a hint of citrus in your tea? Add one to your brewed tea instead of lemon.
6. Turn Kumquats Into Candy
The only additional ingredients you need to make sticky, gooey candied kumquats are sugar and water that gets boiled down. Store candied kumquats in a jar in the fridge, and eat them on their own or with desserts or ice cream.
7. Eat Kumquats Straight
Because their peel and pith are edible, there's perhaps no better way to enjoy kumquats then straight from the tree. Pick kumquats when they've turned completely orange. Leave any kumquats that still have green parts on the branches as these are still turning ripe.
They make a low calorie, tasty, and nutritious snack.