New Zealand Treecrops AssociationKnowledge - GeneralJujubeRoy Hart's take on a UK article John Prince trials at Nestlebrae Exotics
Extract from Martin Crawford article
From the Nelson branch newsletter Feb 2003.
We are inundated today with the marvellous attributes of everything that grows, is eaten, rubbed on, put on the compost heap, or whatever. But from this article I think the Jujube can beat the lot.
Here are some of its attributes.
Zizyphys jujube (synonyms Z. sativa, Z. vulgaris) - jujube, Chinese jujube, red date or Chinese date, have long been grown for their excellent fruit. Natives to Asia where there are many cultivars grown for fruit. However, it has become naturalised in many other warm temperate regions. It was brought into the Mediterranean in ancient Roman times. In China it has the reputation of one of the five principal fruits.
The jujube is a deciduous shrub to 9m high and 7m wide. Drooping branches, flexuous twigs, and pairs of short or long spines. It is very unusual in that it sheds many of its short lateral twigs Therefore it has deciduous twigs as well as deciduous leaves This loss of twigs gives the tree a zigzag appearance in winter. They often send suckers up some distance from the parent shrub.
As spring growth begins, each node of the woody branch sends out 1 to 10 branchlets, most of which fall again in the autumn. Leaves are 2.5 to 6 cm long, elliptical, leathery, and shiny on a short stalk.
Flowers are small and yellow, in clusters of 2 or 3 on current seasons growth They open in late spring or summer depending on temperature. Flowering can go on for a long time. However, individual flowers are only receptive for one day. Pollination is by insects, including bees, and although they are self-fertile, larger fruit are obtained by cross-pollination.
Fruit size is between a cherry and a plum, roundish/egg-shaped, and sometimes pear-shaped. Fruit and everything else is extremely variable between all the various cultivars. The skin is bright green and shiny when the fruit is mature, with the flesh crisp, sweet, with an apple flavour. If left on the tree the skin begins to turn brown in a few spots then goes completely brown. At this stage the fruit begins to dry and wrinkle. By the time it is fully ripe the jujube is a rich red/bronze and resembles a prune or date. Hence the name Chinese date. The texture is now chewy. The fruit contain a single hard-shelled stone that has one or two seeds.
Seedling rootstocks of jujube have a deep strong taproot, making them drought tolerant. The mature plant is winter hardy to -20°C, but shoots may be cut back by less severe frosts if still immature. It has a short chilling requirement and tolerates extreme heat to 40°C.
Uses:
The fruit have a pleasant acid taste when fresh, but are usually allowed to dry becoming chewy and more palatable. They are used in savoury dishes with rice, fish, soup, and cakes and sometimes ground into flour and used for bread. The fresh pulp contains 9% sugar, 1.7% pectin, 2.5% protein, and 350mg vitamin C. Fresh fruit are sometimes used to make jam.
The dried fruit contains 20-35% sugar (sucrose, fructose, glucose) and re rich in vitamin C. Oriental shops sell Chinese dates which have been boiled with sugar and honey, which is the most popular Chinese way of eating them. In Korea jujube flour is used in a hot pepper/soyabean paste. Edible oil can be obtained from the seed. Fruit are also medicinal, and widely used in Chinese herbal medicine, for anticancer, sedative, as a tonic, arthritis, insomnia, treating hepatitis B, nausea, vomiting, abdominal pain in pregnancy, and externally in poultices for wounds. Beat that! In Britain they are often used boiled in honey to alleviate coughs and sore throats, and were formally imported from southern France.
The seeds are used in Chinese medicine for insomnia, amnesia, vertigo, burns, and dyspepsia, for wounds and as a febrifuge (fever). Beat that again.
The leaves are also medicinal, being astringent, febrifuge, and laxative. For scabies and throat troubles, and also made into a broth for treating liver, kidney, and stomach problems, and improve vital functions. And said to improve hair growth. Beat that. Fodder for sheep and goats, and have been used as fodder for silkworms. The wood of the plant is very hard and durable. It makes good fuel and charcoal. Are you getting exhausted, I am.
In China, jujube is widely used in shelterbelts, with over 200,000 ha planted for sheltering cereals such as wheat. Trees are also used to stabilise mountainous slopes from erosion, and are considered one of the best plants for this purpose. You can't beat that.
The leaves have been used as a fungicide against several diseases such as Alternaria in cotton and onions, and Helminthosporium sp. And believe it or not, is an attractive ornamental tree.
Cultivation
Hot dry weather is needed for good fruiting. With prologued severe frosts, the plants need some protection. The plants grow in Britain, but it is not warm enough for good fruiting. They like low humidity and well drained soils.
Pruning should be done in the dormant season, as the fruit are borne on current season's growth there is no danger of pruning off potential fruit. Aim to keep the tree open and well ventilated. In China girdling is commonly used to increase yield. This also causes the tree to set fruit earlier and ripen all together. You can also manipulate the harvest time by the time of girdling.
Fruiting can begin 2 to 4 years after planting for grafted plants. Seedlings come relatively similar to the cultivar parent but take longer to fruit. Although they are self-fertile, fruit is bigger and more numerous with cross-pollination. Yields vary tremendously but can reach 45kg a tree under ideal conditions. Fruit must be picked or shaken from the tree every few days.
Cultivars:
China has currently 400 cultivars, although only a few are available in the West. Good sounding cultivars Lang and Li are available from Britain. There is a very wide variability within the jujube genotype.
I would like to know if any cultivars are in New Zealand, and how they are doing. It seems a plant that we should as Tree Croppers look out for in New Zealand. And a branch or National support work on. Seedlings I know are here. Are there any good ones? Propagation seems fairly straightforward.
This information is taken from an article by Martin Crawford, Agroforestry Research Trust, Devon, UK. I tried to shorten it as much as possible. If the Poms can grow them, we should be able to. I think he is the same person who gave us lots of information on pine nuts several years ago. Roy Hart
Nelson branch newsletter Feb 2003.
John Prince - observations:It is good to see a developing interest in the possibilities of jujubes in NZ amongst some of the longstanding members of the Tree Crops Association. However, from my own experiences, I would urge a cautious approach. I would also point out that a major importation of jujube cultivars into NZ has already been done. Moreover, this information was given by me in the initial address to the 1999 NZTCA Conference in Auckland. Even more interestingly, this fact was recorded on the NZTCA's own website! Try, for example, [clicking this link]. Perhaps it was because I was an Aucklander, mainly talking about subtropical plants of interest for tree croppers in the warmer parts of NZ, but the slides of jujubes that I showed on that occasion, and what I had to say about them, clearly didn't make much impression on some people from colder regions.
http://www.treecrops.org.nz/knowl/addgen/jujube.html |
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