Jujube

Keep water on the tree through fruit sizing

Once fruit has set and is sizing, irrigate through the summer instead of letting the tree ride out the dry spell. Drip irrigation and microsprinklers are both effective ways to deliver it and can double as fertigation (UF/IFAS HS1477). Newly planted trees, bare-root ones especially, need water two or three times a week until they are established. Jujube shrugs off drought, which is exactly why growers under-water it. NMSU is direct about the tradeoff: the plants are quite tolerant to drought, but for a premium fruit set and yield the trees still need to be irrigated in a semiarid climate. The tree survives either way; the crop does not.

Spring nitrogen, measured off the trunk diameter

As growth begins in spring, apply 0.2 lb of actual nitrogen per inch of trunk diameter in a single application, up to a maximum of 1.0 lb per tree. First and second year trees do better on three smaller doses, a third of the total each month across the first three months of growth. Nitrogen is the nutrient jujube actually responds to, and scaling the rate to trunk diameter sizes the dose to the tree instead of guessing at it. Rate and split-application schedule are from Texas A&M AgriLife.

⚠ Do not fertilize a newly planted tree until it has leafed out (NMSU H-330, https://pubs.nmsu.edu/_h/H330/). Avoid heavy applications of quick-release nitrogen, which push leafy growth and increase fruit drop at the expense of the crop (UF/IFAS HS1477, https://ask.ifas.ufl.edu/publication/HS1477). Neither caution appears on the Texas A&M page that carries the fertilizer rate.

Winter pruning: open the canopy but spare the fruiting spurs

Prune while the tree is dormant and leafless. Take out dead, damaged, weak, and competing branches with thinning cuts back to their base, and keep the center open on upright varieties so you can reach the fruit. Leave the short stubby fruiting spurs alone, and shorten secondary shoots to one or two nodes only where you want more branching. Jujube fruit hangs on deciduous branchlets that grow fresh each spring from permanent fruiting spurs on the secondary shoots, so a spur you cut off in winter is a crop you will not pick. One heading cut on a primary shoot stops its extension and turns the tree toward fruiting, while two cuts sprout new primary growth and expand the canopy.

Cut root suckers off at or below the soil line

Jujube throws suckers from its lateral roots, often several feet out from the trunk. Cut them off at or under ground level as soon as they appear, and keep cultivation, tilling, and digging away from the root zone. Root injury is what triggers the sprouting, so cultivating around the tree makes the problem worse rather than better. On a grafted tree the suckers come up from the rootstock, not from your named variety, so they will never bear the fruit you planted and only divert the tree's growth.

Scout the fruit rather than spraying a schedule

Walk the tree while the fruit is sizing and look for larval entry holes in the fruit from peach fruit moth, dark leaf spots from Alternaria, and bird or stinkbug damage. Treat only if you actually find a problem, because there is no routine spray program for this crop. Across twelve years of New Mexico trials jujube was almost disease- and pest-free, turning up only occasional peach fruit moth damage on fruit and an Alternaria alternata leaf spot at a single site. A calendar spray on this tree spends money and chemical against pests that are mostly not there.

⚠ Jujube bloom runs two months or longer and is heavily worked by honey bees, wild bees, and hover flies. Never put an insecticide on this tree while it is flowering.

Pick by color stage, according to what the fruit is for

For fresh eating, pick anywhere from the creamy white mature stage, when skin shifts from dark green to yellow-green and the first brown-red spots show, through to fully red but still firm. For drying varieties wait for fully red, then lay tarps under the tree and shake the branches or knock fruit down with long poles. The two uses want opposite ripeness. Fresh fruit is crisp and at its best before it softens or wrinkles, while sugar keeps loading into a drying cultivar right up to full red, so picking a drying variety early costs you the sweetness that made it worth drying.

Cool the fresh fruit, and dry the drying fruit fast

Fresh fruit picked at first ripe holds two weeks or more at 40F without losing quality. If you are drying and your climate is humid, harvest at fully red and get the fruit into a dryer immediately rather than letting it hang. Letting jujube dry on the tree works in desert air but fails in a humid climate, where yeast and mold infect the fruit before it can ever dry down.