Detailed Guide to the Cultivation and Management of Kinzu (Hong Kong Kumquat) Bonsai
Kinzu (Fortunella hindsii) is native to the rocky areas of the hilly regions in the southern provinces and autonomous regions of China. It grows slowly and is easy to shape, making it an excellent material in the hands of bonsai artists. The kinzu tree is vigorous and is an ideal bonsai species valued for its leaves, trunk, and fruit alike. Its ornamental value is very high during the fruiting period, and in Japan it is regarded as a precious bonsai treasure. Kinzu is an ornamental fruit plant that can be planted in clumps or patches at forest edges or around buildings, and can also be grown in pots and made into bonsai.
Kinzu can hold its fruit until as late as May 1 of the following year. Holding fruit for too long will affect the growth of the following year. Generally around New Year's Day, the fruit is removed by hand. Kinzu fruit is sweet and sour and can be eaten after being preserved with white sugar. So how should kinzu bonsai be cultivated and managed? Below, the editor will introduce it to everyone.
1. Time for Collecting from the Mountains
The best time is from the end of March to the beginning of May each year, when the survival rate of the tree stumps is the highest.
2. Method for Raising the Rough Stock
Use a very thin single layer of plastic film (such as cling film) to wrap the branches and trunk before planting. Wrapping the trunk with cling film can achieve the purpose of moisture retention. In early May, when new buds of kinzu emerge, they can break through the single layer of cling film. In cold years or for tree stumps with many branches, multiple layers of cling film can be used for wrapping, but when the new buds of kinzu grow, the film needs to be manually pierced. For raising kinzu rough stock, use plain, clean soil, without too much fertility; loose and breathable yellow mud is best.
3. Time for Potting
Wait until the rough stump has sent out new branches and leaves; at the earliest, it can be potted in the second half of the same year. If time permits, it generally needs to be tended for more than 2 years. After that, the most suitable time for repotting is after Qingming (April 5), and another relatively suitable time is the end of August to the beginning of September.
4. Preparation of Potting Soil
The soil should be somewhat fertile; an appropriate amount of cake fertilizer and leaf mold can be added.
5. Potting Method
Kinzu can be potted with the original soil around the roots, or with bare roots. When potting with bare roots, overly long thick roots can be appropriately shortened, which helps stimulate new root growth.
6. Temperature Management
Kinzu can tolerate high summer temperatures, but in winter, when the temperature is below -5°C, cold protection measures need to be taken; generally, plastic film or straw, etc., can be used as cover.
7. Fertilizer and Water Management
Water management is the same as for common flowering plants: water when dry and let dry between waterings, alternating between dry and moist. Kinzu bonsai is prone to dying if the water is too dry. Newly potted plants must not be fertilized. Generally, if the potting soil is fertile, there is no need for additional topdressing. If the potting soil has poor fertility, a light application of some quick-acting compound fertilizer can be made as appropriate. Generally, for a flower pot with a diameter of 25 cm, more than 10 granules of compound fertilizer can be broadcast. The time for topdressing is before kinzu sprouts, with Qingming season being best. Kinzu sprouts above 25°C, and generally sends out new buds in early May. The number of topdressings should preferably be 1.
8. Pruning Method
(1) Growth speed of new branches of kinzu. The author conducted a survey on October 15, 2013, and the survey subjects were a batch of kinzu potted during the Qingming season in 2011.
(2) Pruning time. Generally, pruning is done after Qingming and before the Beginning of Autumn. Pruning is not advisable after the Autumn Equinox, because pruning too late easily triggers autumn shoots. Autumn shoots have not fully lignified before winter arrives and are prone to freezing damage.
(3) Pruning method. If the goal is to raise rough stock, there is no need to prune new branches every year. For the cultivation of fine kinzu bonsai, when a new branch grows to about 1/3 of the thickness of the mother branch, the new branch can be shortened, generally leaving 2 to 3 buds at the base.
The kinzu tree has a graceful posture, an evergreen body, and charming red fruit, making it an excellent tree species for home potted greenery decoration. So how should potted kinzu be grown so that it bears abundant fruit every year? Let us take a specific look below.
1. It should be planted in loose, fertile, well-drained, slightly acidic loam soil. Repot and change the soil once every 2 to 3 years from winter to before budding the next spring; cut off dead roots, shorten leggy roots, switch to a pot one size larger if the pot is small, remove 1/3 to 1/2 of the old soil, and supplement with new culture soil (the culture soil can be made by mixing 40% leaf mold, 35% yellow soil, and 25% freshwater sand). When using it, some barnyard manure or "compound fertilizer" can be added as base fertilizer (bottom fertilizer), then water thoroughly and manage according to routine care.
2. Usually, do not water unless the soil is dry; when dry, water thoroughly. During the growing season, the potting soil should be kept moist. During the "dog days of summer," protect it from exposure to the scorching sun, increase the amount of watering, and spray water (mist) on the plant.
3. It likes fertilizer. During the growing season, it is best to apply a black sulfur aqueous solution 2 times (either alone or mixed), to ensure the potting soil remains slightly acidic. Before flowering and after fruiting, it is advisable to apply more phosphorus and potassium fertilizer.
4. In spring, remove the fruit, thin out overly dense branches, and shorten the remaining current-year branches.