Plant problems

Why Are My Jasmine Leaves Curling?

Q: Why are my jasmine leaves curling?

Jasmine (Jasminum) leaves curl most commonly in the UK because of aphid infestation on the young shoot tips, jasmine rust (Puccinia jasminearum), drought stress, or cold damage on less hardy species. The two species most widely grown in UK gardens are Jasminum nudiflorum (winter jasmine), a deciduous, scrambling wall shrub from China with bright yellow flowers on bare green stems from November to February, and Jasminum officinale (common jasmine or poet's jasmine), a vigorous, semi-evergreen or deciduous twining climber from the Himalayas with intensely fragrant white flowers from June to September. Aphids are the most common cause of leaf curl on Jasminum officinale in particular: the soft, pinnate leaves and young shoot tips are colonised by greenfly in spring and summer, causing the leaflets to curl inward and the growing tips to distort. Jasmine rust (Puccinia jasminearum) is a fungal disease that produces bright orange or rust-coloured pustules on the leaf undersides; affected leaves develop corresponding yellow spots on the upper surface and may curl and drop prematurely; the disease is becoming more common on outdoor jasmine in the UK as the pathogen spreads. Drought stress causes Jasminum officinale leaves to curl and yellow in containers or in dry, freely draining soils during hot UK summers. Jasminum nudiflorum, being very hardy, rarely has pest or disease problems; it can look tatty after a harsh winter but regenerates reliably.

Q: How do I prune jasmine in the UK?

Jasminum nudiflorum (winter jasmine) and Jasminum officinale (common jasmine) are pruned at different times because they flower at different seasons. Jasminum nudiflorum flowers on the previous year's shoots in winter (November to February); prune immediately after flowering (February to March) by cutting all the flowered stems back to a few centimetres from the main framework. This removes the old flowered wood and encourages the production of long, vigorous new green shoots through summer and autumn; these new shoots will carry next winter's flower buds. Hard pruning of winter jasmine after flowering, or complete renovation by cutting the whole plant back hard to the main framework in March, produces the best display the following winter. Jasminum officinale (common jasmine) flowers on the current season's growth in summer; prune in late winter or early spring (February to March) before new growth begins. Cut back the main stems by about one third and remove all weak, dead, or congested shoots to open up the structure and encourage strong new flowering shoots. Jasminum officinale is a vigorous climber that can become very tangled and congested if not pruned regularly; annual pruning in late winter keeps the plant manageable and well-flowering. Both species tolerate hard renovation pruning; a Jasminum officinale that has become a congested mass can be cut back hard to 30 to 45 cm from the base in February and will regenerate vigorously, producing a fresh, flowering plant within one to two seasons.

Q: Is Jasminum officinale hardy in the UK?

Jasminum officinale (common jasmine or poet's jasmine) is generally hardy throughout most of the UK but is not fully frost-tolerant in the coldest northern gardens or in particularly severe winters; it is hardiest in its deciduous state (losing its leaves and going fully dormant in winter) and least hardy when retained as semi-evergreen in mild conditions, when the retained leaves can be damaged by hard frost. In most of southern and central England, Wales, and Ireland, Jasminum officinale survives UK winters reliably on a sheltered wall or fence; it is semi-evergreen in mild areas (retaining some leaves through mild winters) and fully deciduous in colder areas or harsh winters, regrowing vigorously in spring. In the coldest UK gardens (exposed northern England and Scotland, particularly at altitude), Jasminum officinale may be cut back by hard frost in severe winters, though it typically regrows from the base in spring. The cultivar 'Argenteovariegatum' (grey-green leaves with cream margins) and 'Aureum' (yellow-variegated leaves) are similarly hardy to the plain-leaved form. Jasminum nudiflorum (winter jasmine) is fully hardy throughout the UK to at least -20°C and can be grown in all UK regions; it is one of the hardiest garden shrubs available and one of the few ornamental plants that flowers reliably in December and January in a normal UK winter. The semi-hardy species Jasminum polyanthum (pink jasmine) and Jasminum sambac (Arabian jasmine) are tender and suitable for UK conditions only as conservatory or cool greenhouse plants; they are not hardy outdoors.

Q: What is jasmine rust and how do I control it?

Jasmine rust (Puccinia jasminearum) is a fungal disease specific to jasminum plants; it produces bright orange-yellow pustules (uredinia) on the undersides of the leaves, with corresponding yellow spots or patches on the upper leaf surface; affected leaves may curl, yellow, and drop prematurely, and severe infections can weaken the plant significantly. The disease spreads by airborne spores from infected plants and is most severe in warm, humid conditions with poor air circulation. Jasmine rust was relatively uncommon in the UK until the early 2020s but has become increasingly widespread as the pathogen spreads northwards; it is now encountered regularly on outdoor Jasminum officinale and related species in UK gardens, particularly in the south and east of England in warm summers. To control jasmine rust: remove and destroy affected leaves as soon as orange pustules are noticed; do not compost infected material as the spores can remain viable. Apply a copper-based fungicide or a proprietary rust fungicide to the plant; both organic copper fungicides and systemic fungicides such as tebuconazole are registered for use on ornamental plants and are effective against rust fungi when applied before infection is severe. Improve air circulation around the plant by thinning congested growth; rust is worst in still, humid conditions. The annual spring pruning of Jasminum officinale (cutting back the old growth before new growth begins) removes overwintered infected material and can significantly reduce the infection level the following season. Severely infected plants that are defoliated by rust in most years may be better replaced with a fresh, disease-free plant in a more open, airy position.

Jasmine (Jasminum) includes two of the most widely grown UK garden climbers: Jasminum nudiflorum (winter jasmine), fully hardy with yellow flowers on bare stems from November to February; and Jasminum officinale (common jasmine), a vigorous twiner with intensely fragrant white flowers from June to September. The soft leaves of Jasminum officinale attract aphids in spring and summer; jasmine rust, which produces orange pustules on leaf undersides, is an increasingly common cause of leaf curl and early leaf drop across the UK.

Aphids

Aphids are the most common cause of leaf curl on Jasminum officinale in spring and summer; the soft, pinnate leaves and tender young shoot tips are colonised by greenfly in April and May, causing the leaflets to curl inward, the growing tips to distort, and the plant to look untidy during the main growth flush. Heavy aphid pressure produces honeydew, which attracts sooty mould and ants. Natural predators (ladybirds, lacewings, parasitic wasps) typically arrive within 3 to 4 weeks and reduce colony numbers significantly; the vigorous growth of Jasminum officinale rapidly outpaces the damage in most years.

What to do

On most occasions no treatment is needed; natural predators and vigorous plant growth resolve the infestation. Pinch off the most heavily colonised shoot tips to remove large colonies quickly. Apply insecticidal soap or a jet of water to dislodge aphids from accessible shoots. Avoid high-nitrogen fertilisers that encourage the soft, fast-growing shoot tips most attractive to aphids. Jasminum nudiflorum is rarely seriously affected by aphids.

Jasmine rust

Jasmine rust (Puccinia jasminearum) is a fungal disease producing bright orange-yellow pustules on the undersides of jasmine leaves; corresponding yellow spots appear on the upper surface, and affected leaves curl, yellow, and drop prematurely. The disease is most severe in warm, humid, still conditions and has become increasingly common on UK outdoor Jasminum officinale in recent years as the pathogen has spread. Severe infections can defoliate the plant and weaken it significantly, reducing flowering in the same season.

What to do

Remove and destroy infected leaves as soon as orange pustules appear; do not compost. Apply a copper-based or systemic rust fungicide (such as tebuconazole) to the whole plant before infection is severe; repeat as directed on the product label. Improve air circulation around the plant by thinning congested growth and avoiding planting in still, enclosed positions. Annual spring pruning removes overwintered infected material and reduces the following season's infection load significantly. In positions where rust recurs severely each year, consider replacing the plant in a more open, airy site.

Drought stress

Jasminum officinale in containers or in freely draining soils can suffer drought stress in hot UK summers; the pinnate leaves curl and the leaflets begin to yellow when moisture demand exceeds supply. The plant prefers reliably moist but well-drained soil; in the ground in an average UK soil, drought stress is uncommon on established plants, but container-grown jasmine and plants against south-facing walls where the soil dries out rapidly can be affected. Jasminum nudiflorum is more drought-tolerant than Jasminum officinale and rarely shows drought stress in UK conditions.

What to do

Water container-grown jasmine regularly in summer; check the compost every 2 to 3 days in warm weather and water when the top 5 cm is dry. Mulch the root zone of ground-planted specimens with composted bark to conserve moisture. Wall-base soil at the foot of south-facing walls tends to be particularly dry; ensure adequate irrigation and mulching in these positions. Feed with a balanced liquid fertiliser monthly through summer to support the vigorous growth and flowering season.

Cold damage

Jasminum officinale is generally hardy throughout most of the UK but the retained semi-evergreen leaves can be damaged or killed by hard frost below about -10°C, turning yellow-brown and curling before dropping; the plant typically regrows vigorously from buds on the main stems in spring. Jasminum nudiflorum is fully hardy to at least -20°C and is never affected by cold damage in UK conditions; its bare stems simply continue to produce yellow flowers through the coldest months. On Jasminum officinale, the annual late-winter pruning removes any cold-damaged growth and stimulates a fresh season of vigorous, flowering stems.

What to do

Grow Jasminum officinale against a sheltered south or west-facing wall in colder UK gardens; the wall provides frost protection and reflected warmth. Do not cut back cold-damaged shoots until spring when new growth confirms the extent of damage. The annual late-winter pruning naturally removes cold-damaged material; no additional action is usually needed. In the coldest exposed UK gardens, Jasminum nudiflorum is the more reliable choice for reliable winter interest.

Frequently asked questions

Why are my jasmine leaves curling?

Jasmine leaves curl most commonly because of aphids on young shoot tips in spring and summer (the most common cause on Jasminum officinale; curling and distortion of new leaflets), jasmine rust (orange-yellow pustules on leaf undersides with corresponding yellow spots above; leaves curl and drop prematurely), drought stress in containers or dry wall-base soils, or cold damage on the semi-evergreen leaves of Jasminum officinale in hard winters. Jasminum nudiflorum is very hardy and rarely troubled by any of these problems.

How do I prune jasmine in the UK?

Prune Jasminum nudiflorum (winter jasmine) immediately after flowering in February to March: cut all flowered stems back hard to the main framework to promote long new shoots for next winter's flowers. Prune Jasminum officinale (common jasmine) in late winter or early spring: cut back main stems by one third and remove weak, dead, and congested growth. Both species tolerate hard renovation pruning cut back to 30 to 45 cm from the base.

Is Jasminum officinale hardy in the UK?

Jasminum officinale is generally hardy throughout most of the UK, surviving on a sheltered wall in most UK winters; in cold northern gardens it may be cut back in severe winters but regrows reliably from the base. The semi-evergreen leaves can be damaged by frost below -10°C. Jasminum nudiflorum (winter jasmine) is fully hardy to at least -20°C and can be grown everywhere in the UK without protection.

What is jasmine rust and how do I control it?

Jasmine rust (Puccinia jasminearum) produces bright orange pustules on leaf undersides with corresponding yellow spots above; affected leaves curl and drop early. It has become increasingly common on UK outdoor Jasminum officinale. Remove infected leaves promptly; apply copper-based or systemic rust fungicide; improve air circulation by thinning congested growth. Annual spring pruning removes overwintered infected material and significantly reduces the following season's infection.