Growing Kumquat Trees

Kumquats (or cumquats, Fortunella spp.) are small, evergreen citrus trees that produce heavy crops of small orange colored fruit which have a sweet edible rind and sour flesh. Kumquats can be eaten whole out of hand or used in a varieties of recipes. Kumquats make great additions to small gardens in which they provide an edible, vertical feature plant that won't grow into a monster like many other citrus trees eventually do. Kids also get a kick out of growing these 'miniature oranges'. There are many different cultivars of kumquat available, this article provides a general overview of cumquat varieties and provides some tips for growing them successfully.

Kumquats have been divided into three variety groups and each of these have been assigned their own species epithet, although they will hybridize with each other and even with other citrus species. While some cultivars are quite tolerant of frosts, most will actually produce bigger and sweeter fruits when grown in warm climates.

Nagami Kumquats

Nagami kumquats (Fotunella margarita) produce orange, oval or egg-shaped fruit during Winter. Nagami kumquats grow to around 4m tall with a spread of 3m, depending on the particular cultivar. The flowers are the most fragrant of all the kumquat types. The bushes are very ornamental with attractive flowers, foliage, and of course, fruits. This varieties is the sweetest of the kumquats and is well suited for eating out of hand or making marmalade, liqueurs or crystallized sweets. Nagami Kumquats are frost hardy and can withstand temperatures as low as 14 degrees Fahrenheit (-10 degrees Celsius). They do however require a hot summer with temperatures between 77 and 100 degrees Fahrenheit to do well, otherwise they will grow very slowly. Nagami kumquats have a shorter growing season than other kumquats and become dormant earlier in Autumn which makes them much more frost resistant than the other varieties.

Marumi or Morgani Kumquats

Marumi kumquats (Fortunella japonica) produce pale orange or golden coloured, round-shaped fruit. The flesh of marumi kumquats is very sour, a striking contrast to the sweetness of the peel. Mauri kumquats can be grown as an ornamental, with some varieties having attractive variegated foliage. It is also well suited to container growing and they are sometimes even used in bonsai. The fruits of this variety are often given during Chinese Lunar New Year as a good luck charm. They are well suited for making marmalade and jellies. Plants are mildly frost hardy and tend to grow a little smaller than other varieties, they only grow to a maximum of about 2.5m tall. Marumi kumquats are the most commonly grown of the three variety groups by home gardeners.

Jiangsu Kumquats

Jiangsu kumquats (Fortunella obovata) produce bright orange, round or bell-shaped fruits. Jiangsu kumquats are easily distinguished from the other two groups as they have round leaves. They can be grown for fruit or for their ornamental value, but unlike the other two groups Jiangsu kumquats have no tolerance to frost.

Fortunella × Citrus Hybrids

There are many interesting kumquat hybrids available and they have been given equally interesting names, some of these include:

Limequat Key Lime (Citrus aurantifolia) × Kumquat. This hybrid has extremely sour, bright green skin. Not suitable for eating raw but good for cooking or making into jams.

Procimequat Limequat × Kumquat. A second generation cross producing somewhat sweeter skinned, golden coloured fruits.

Sunquat Lemon (Citrus × limon) × Kumquat. There is some dispute as to whether the sunquat is actually a lemon or clementine hybrid. Nether the less the fruit make an excellent marmalade.

Mandarinquat Mandarin (Citus × reticulata) × Kumquat. Similar in taste to non-hybrid kumquats but with much larger fruit.

Orangequat Satsuma Mandarin (Citus × reticulata) × Kumquat. This one is not actually an orange hybrid at all but a satsuma mandarin hybrid. The fruit have a mild flavour and thick rind.

Citrangequat Trifoliate Orange (Citrus × insitorum) × Kumquat. Produces very acidic fruit but they are extremely frost hardy.

Calamondin Sour Mandarin (Citrus sunki) × Kumquat. Sour flesh and skin, the juice is used in a similar fashion to lime juice in cooking and drinks.

When planting your kumquat tree, choose a sunny position with fertile, free draining soil. Dig the hole about twice the width of the root-ball of the plant. Incorporate lots of compost into the soil when back-filling if the soil is lacking in organic matter. Mulch around the plant well but avoid having the mulch touch the base of trunk otherwise the tree may rot. Alternatively you can plant your kumquat into a large container filled with a free draining, premium potting mix. You can use two container grown plants to make an elegant feature by flanking either side of an entrance-way with them. Water your kumquat tree straight away after planting and again the following day, then twice weekly for the first month. Apply organic citrus food according to the directions on the packet and water weekly during the growing season (especially during the first years growth) for best results.

I hope you enjoy growing this wonderful citrus tree.