Propagation

Seed

Jujube seed
Propagation from seed is possible but is not for the impatient. Seeds from grafted trees should not be used as they lack vigour and will not be true to type. The best results are obtained from rootstock plants that have been allowed to fruit and the seeds harvested.

Traditional advice is that the seeds should be stratified for 3 months in a warm environment followed by 3 months in a fridge before being planted out. However Roger Meyer suggests in his Jujube Primer [2] that the process can be accelerated by splitting open the stone and accessing the seeds directly. Care should be taken while doing this as it's easy to cut your fingers when using sharp implements as the stone is very hard.

Germination can be slow. If you plant the stone then some may not even emerge until the following spring (12 months later). Seedlings should be potted up into individual pots a few weeks after germination.

The plant needs to be approximately pencil size in width before it can be considered ready for grafting. This may take some considerable time.

See the Cultivation section for details on grafting and budding

Root cuttings of Zizyphus jujuba

Cuttings

Propagation from conventional cuttings produces disappointing results. Occasionally the odd one does survive but the vast majority just shrivel and die even with extreme care.
In contrast, reasonable success can be had from root-cuttings - i.e. cut sections of Jujube root. Ideally the root should be around 8-10mm in width but some success can be had with cuttings as small as 5mm although the process does take a little longer. We tend to plant the sections out vertically with the top just poking above the soil. After a few weeks the cambium layer just under the bark seems to swell and take on a white appearance. A few days later small green shoots start to appear. Multiple shoots will start sprouting but these should be thinned to the strongest one so that any growth that does occur is put into a single stem. Rooting hormone appears to be unnecessary although we are currently trialling a batch that has been split 50/50 so that half did and half didn't have a hormone dip prior to planting.

The cuttings need to be kept in a humid environment so some kind of plastic cover is ideal. Mist every few days to maintain the humidity but don't waterlog them. Be sure to keep the container out of direct sunlight or your mini-greenhouse will quickly turn into an oven and you'll lose the lot.

Jujube root sucker

Root Suckers

This is probably the most common method of propagation of new plants. Unfortunately it requires that you have a mature existing tree that is several years old (older than the one in the picture) otherwise it will rob all the energy from the parent plant. Jujubes tend to sucker from the roots. On young trees this is normally near the base of the plant but as the tree matures this can be several metres from the trunk. Allow some suckers to remain and in the dormant period sever the connection to the parent plant. This forces the root sprout to form its own root system rather than relying on that of its parent. When the sprout is around pencil size in thickness it is suitable for grafting. For best results graft in-situ without moving the sucker from its original location. When you can see that the graft has taken, the plant can be dug up and moved, although it's preferable to do this in winter when the plants are dormant.

Zizyphus jujuba plantlet in sterile tissue culture

Tissue Culture

We are experimenting with this at the moment but the set-up costs and technical difficulty make this unsuitable for the amateur or home gardener.

Our early tests indicated that the Jujube is quite resilient to strong disinfectants which is good as it increases the chances of harvested plantlets being free of bacteria and fungi - essential for anything that has to grow in a sealed vessel. Gel media has to be autoclaved and requires a delicate balance of nutrients and pH adjustment to get the mixture just right. Micro-scales are required as you will be measuring things in single grams, as is a sound understanding of aseptic technique. This is definitely not something to be undertaken lightly.

The main problem we face right now is that the plantlets do not grow fast enough in between transfers to make this a viable means of propagation. They are also susceptible to vitrification (plant tissue turns translucent) if left too long in sealed vessels. We are experimenting with vented caps on our culture vessels but so far results are inconclusive. Temperature range also appears to be quite narrow - too cold and nothing happens, one hot day and they can all die.

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