Rootstock
Rootstocks used in northern China are Chinese jujube and its direct ancestor sour jujube (Z. acidojujuba). Sour jujube is not permitted entry into Australia. In Western Australia, jinsilin is used as a rootstock.
Suckers
Jujubes are known for having prolific offshoots or suckers, mainly on lateral roots with diameters of 5-10 mm. The use of suckers is a common method for propagation of jujubes.
Seed preparation for rootstock
Fully matured jujube stones and kernels (seeds) can also be used to grow rootstock seedlings. Jujubes have a hard stone containing two, one or no seeds, depending on the cultivar. For better germination the seeds should be removed from the stone before planting.
Rootstock fruit should be collected or purchased in autumn. The fruit should be soaked in water for several hours then the pulp removed until the stones are clean. The clean, dry stones should be kept in paper bags until stratification. Jujube seeds can germinate without stratification, but stratification makes germination easier and more reliable.
The stones should be stratified in moist sand for 3–4 months at 2–5°C before sowing. The stones are mixed with wet sand at a 1:3 ratio by volume and can be stored in pots or plastic bags. The seeds (removed from the stone) need to be soaked in water for 1–2 days before sowing.
Treated seeds are sown in early spring at a depth of 2cm, 10–15 cm apart within the rows and 40–50 cm apart between rows. Approximately 75–150 kg of stones or 20–30 kg of seed is needed per hectare. Seedbeds can be covered with plastic film to promote germination.
Rootstock seedling management
Although jujubes are drought tolerant, adequate water supply in the nursery is essential. It has been reported that maintenance of pre-irrigation moisture of 80% in the nursery soil has been helpful in the development of over 98% Chinese jujube seedlings (to be used for budding).
Seedlings should be fertilised regularly from when they are 7–10 cm tall to enhance growth. Once the plants reach 60 cm or so in height, trunk diameter growth can be encouraged by pinching the growing tip with your fingers and removing the lower branches to make grafting easier. Some of the seedlings should be ready for grafting after one year of growth and all plants should be ready after two years.
Scionwood
Due to jujubes unique shoot structure most of the side branches are not thick enough to be used as scionwood, making the primary shoots the most often used scionwood source. Each primary shoot only has 5 to 8 nodes that can be used for grafting. Due to the lack of scionwood, a single jujube bud piece is often used for grafting. One-year-old shoots are the best scionwood; however shoots up to three years old can also be used for grafting. Scions from 1–2 year old extension shoots have been very successful.
Scionwood Storage
Waxing the scionwood is recommended to keep the wood from drying out if it is not going to be used for a month or more or if shipped from another location. Store the waxed or original scionwood (with some wet paper towels to keep them moist) in the refrigerator until grafting. If the scionwood is collected locally and will be used within 2 to 3 weeks, waxing is not necessary.