Plant problems

Why Are My Jujube Leaves Curling?

Q: Why are my jujube leaves curling?

Jujube (Ziziphus jujuba), also called Chinese date, leaves curl most commonly in the UK because of aphid infestation, drought stress, or witches' broom disease. Several aphid species, including Aphis jujubicola and various general plant aphids, colonise the growing tips of jujube in spring, causing the small, glossy leaves to curl and distort at the shoot tips; heavily infested shoots become stunted. Drought stress is a common cause of leaf curl on UK-grown jujube, particularly in containers or in dry, free-draining soil in a warm, sheltered position; the small leaves curl and roll inward at the margins in response to water deficit and excess heat. Witches' broom (caused by Candidatus Phytoplasma ziziphi) is a serious disease of jujube in China and parts of Asia; it causes a characteristic dense proliferation of shoots (the 'broom') at the branch tips and significantly distorted, curled, pale leaves. Witches' broom is not known to be established in the UK, but plants imported from affected regions may carry it; sourcing plants from reputable UK nurseries greatly reduces the risk.

Q: What does jujube taste like?

Fresh jujube (Ziziphus jujuba) has a distinctive flavour that varies with ripeness: when green (before colour change), the fruit is crisp, mild, and slightly sweet with a texture resembling a firm apple; when fully ripe and red-brown, the flavour develops into something richer, sweeter, and more complex, with notes of date, apple, and vanilla. Slightly wrinkled, over-ripe fresh jujubes become soft, date-like, and very sweet. Fully dried jujubes (hongzao in Chinese cooking) have a wrinkled, leathery texture and a concentrated, intensely sweet, date-like flavour with a slight floral note; this is how jujube is most widely eaten in China, where it has been cultivated for over 4,000 years. In Chinese cooking, dried jujubes are used extensively in teas, soups, porridge, desserts, and rice wine; red dates are considered tonifying in traditional Chinese medicine and appear in countless food remedies for fatigue and blood health. UK-grown jujubes eaten fresh in September (ripe red-brown, with firm flesh and a sweet apple-date flavour) are a revelation for growers who have only encountered the dried version.

Jujube (Ziziphus jujuba), also called Chinese date, is a small deciduous tree with a 4,000-year history of cultivation in China and now increasingly grown in UK gardens and against south-facing walls for its sweet, apple-flavoured fresh fruit and the intensely sweet dried dates valued in Chinese cooking. Hardier than most people expect (tolerating -15°C when dormant) and drought-tolerant, it is a surprisingly achievable fruit tree for UK conditions. When the small, glossy leaves curl, the most common causes are aphids on the spring growth or drought stress in a warm, dry summer.

Aphids

Aphids, including Aphis jujubicola and various general plant aphids, colonise the growing tips of jujube in spring and early summer, causing the small, glossy leaves to curl and distort at the shoot tips. In the UK, where jujube leafs out very late (often not until June), aphid attack on the new spring growth can seem alarming, but populations are generally controlled by natural predators within a few weeks. The infested leaves remain curled even after the aphids are gone; new growth produced after the infestation will be normal.

What to do

Check the growing tips from late spring. Apply insecticidal soap or neem oil to the shoot tips and leaf undersides if populations are heavy. Encourage natural predators. In most UK conditions, a moderate aphid attack on jujube in spring does not require intervention; the tree is vigorous and quickly outgrows the affected shoots.

Drought stress

Jujube is drought-tolerant in the ground but can suffer from water deficit in containers or in the very free-draining, light soils against a warm wall where it performs best in the UK. In a hot, dry UK summer, the small leaves curl and roll inward along the midrib in response to water deficit and heat; the tree may also drop leaves prematurely in a severe drought. The same warm, sheltered, sunny wall position that encourages fruit ripening also increases water demand and the risk of drought stress.

What to do

Water wall-trained jujube thoroughly during dry spells in summer, particularly while the fruit is developing. Apply a deep mulch of wood chip or bark around the base to retain soil moisture. Container-grown jujubes need regular watering throughout the growing season. Jujube in the ground with a reasonable soil depth rarely needs watering in typical UK summers once established.

Witches' broom

Jujube witches' broom (Candidatus Phytoplasma ziziphi) is a serious disease in China and parts of Asia that causes dense clusters of spindly stunted shoots at branch tips, distorted pale curled leaves, poor fruit set, and eventual tree decline. It is transmitted by leafhoppers that are not currently established in the UK, so it is not a practical risk for UK-grown jujube purchased from domestic nurseries. The risk exists if plants are imported directly from affected regions; always buy from established UK nurseries that propagate their own stock from disease-free material.

What to do

Source plants only from reputable UK nurseries. If a plant shows dense broom-like shoot proliferation, distorted pale leaves, and poor fruit set, consult a plant health advisor before removing it; the symptom description overlaps with some physiological responses to hard pruning. Confirmed witches' broom has no cure; infected plants should be removed.

Scale insects

Scale insects, particularly soft scale (Coccus hesperidum) and brown scale (Parthenolecanium corni), can affect jujube in UK garden conditions, particularly on plants grown against walls where natural predator access is reduced. Scale clusters on the stems and undersides of leaves, producing honeydew and sooty mould; heavily infested leaves yellow and the stem growth weakens. Scale is more likely to be a problem on jujube in a heated greenhouse than on wall-trained specimens outdoors.

What to do

Scrub scale off stems with a toothbrush and insecticidal soap in winter when the tree is dormant. Apply a horticultural oil or insecticidal soap spray to active infestations on the young growth. Introduce Metaphycus helvolus for biological control of soft scale. Prune to improve air circulation around wall-trained specimens; good air movement reduces scale establishment.

Frequently asked questions

Why are my jujube leaves curling?

Jujube (Ziziphus jujuba) leaves curl most commonly in the UK because of aphid infestation, drought stress, or (rarely, from imported plants) witches' broom disease. Aphids colonise the growing tips in spring, causing the small leaves to curl and distort; natural predators usually control populations within a few weeks. Drought stress causes the leaf margins to curl and roll inward; water wall-trained specimens during dry spells. Witches' broom (a phytoplasma disease from Asia) causes broom-like shoot clusters and distorted curled leaves but is not currently established in the UK.

Can I grow jujube in the UK?

Jujube (Ziziphus jujuba) can be grown successfully in the UK, particularly in warmer southern and eastern counties. It is much hardier than most people expect, tolerating -15°C when dormant. Best grown wall-trained against a south- or southwest-facing wall, which provides warmth and reflected heat to ripen the fruit. It leafs out very late (often June), which is normal. The fruit ripens from green to red-brown in September and October in good summers; in a greenhouse or polytunnel, reliable ripening is achievable across the UK.

What does jujube taste like?

Fresh ripe jujube has a sweet, apple-like flavour with notes of date and vanilla; when green it is crisp and mild. Dried jujubes (hongzao) have a concentrated, intensely sweet, date-like flavour and are used extensively in Chinese cooking in teas, soups, desserts, and rice wine. UK-grown jujubes eaten fresh in September (ripe red-brown with a sweet apple-date flavour) are a revelation for those who have only encountered the dried form.

What is jujube witches' broom disease?

Jujube witches' broom is caused by a phytoplasma (Candidatus Phytoplasma ziziphi) transmitted by leafhoppers. It causes dense clusters of stunted shoots, distorted pale curled leaves, poor fruit set, and eventual tree decline. It is a serious problem in China but is not currently established in the UK; the transmitting leafhoppers are not established here. Source plants only from reputable UK nurseries to avoid the risk from imported material. Confirmed witches' broom has no cure; infected plants must be removed.