Plant problems

Why Are My Actinidia Leaves Curling?

Q: Why are my actinidia leaves curling?

Actinidia (kiwi vine) leaves curl most commonly in the UK because of drought stress, late frost damage to the emerging spring shoots, aphid infestation, or leaf scorch in exposed positions with dry, hot conditions. The genus Actinidia includes several species grown in UK gardens: Actinidia deliciosa (fuzzy kiwi) and Actinidia chinensis (golden kiwi) are grown for their edible fruit but need a long, warm season to fruit reliably in the UK and are best in sheltered, sunny positions in southern England; Actinidia kolomikta is the species most commonly grown as an ornamental climber, grown for its striking heart-shaped leaves that develop spectacular pink and white variegation on the male plant in the presence of good sunlight; and Actinidia arguta (hardy kiwi) produces small, smooth-skinned, grape-sized fruits that are better suited to UK conditions than the larger fuzzy kiwi and can fruit reliably in southern England on a warm, sheltered wall. Drought stress causes the large, soft leaves of all actinidia species to curl and develop brown edges when the root zone dries out; all species need consistently moist, well-drained, fertile soil and suffer in dry, hot conditions, particularly when newly planted. Late frost in April and May damages the tender new shoots and leaves as they emerge, causing blackening, wilting, and curling of the affected growth. Aphids colonise the young shoot tips and leaf undersides in spring, causing the leaves to curl around the colonies and the growing tips to distort.

Q: Why do cats like actinidia?

Actinidia kolomikta in particular is highly attractive to cats; the leaves of both Actinidia kolomikta and Actinidia polygama contain actinidine and related iridoid compounds that produce a catnip-like response in domestic cats. Cats are attracted to all parts of the plant but most strongly to the young growth and the root area; they roll on the plant, bite the stems and leaves, scratch the bark, and dig around the roots, and can inflict severe damage on young plants in a short time. The damage caused by cat attention can be mistaken for other causes of leaf curl: bitten and torn leaves curl and distort, scratched bark may girdle and kill stems causing wilting above the damage, and root disturbance causes water uptake problems and whole-shoot wilt. Actinidia deliciosa (fuzzy kiwi) and Actinidia arguta (hardy kiwi) are less attractive to cats than Actinidia kolomikta but are not immune to attention, particularly from cats that have been exposed to the scent of Actinidia kolomikta nearby. The cat-attracting properties of Actinidia kolomikta are produced by volatiles that are released when the leaves are damaged; healthy, undamaged leaves produce less scent and attract less attention, so the problem can escalate once cats begin to investigate a plant. The only reliable protection for young actinidia plants (before they become large and robust enough to tolerate cat attention) is physical protection: surround the plant with spiky material (holly cuttings, bramble prunings, cut pine cones), wrap the lower stems with chicken wire, or construct a temporary cage of wire mesh around the plant for the first two to three years after planting.

Q: How do I grow actinidia in the UK?

Actinidia needs a sunny, sheltered wall position, consistently moist but well-drained, fertile soil, and a strong support structure to thrive in UK conditions. All actinidia species are vigorous climbers that can cover a large wall surface quickly; Actinidia deliciosa (fuzzy kiwi) can exceed 9 m in height in a warm, sheltered position and needs very strong wires or a robust trellis to support it. For fruiting: all actinidia species except some self-fertile cultivars require both a male and female plant to set fruit; one male plant can pollinate up to eight female plants. The male Actinidia deliciosa cultivar 'Tomuri' is sold to pair with the female cultivar 'Hayward' (the variety most commonly seen in shops); for Actinidia arguta (hardy kiwi), the self-fertile cultivar 'Issai' is a good choice for smaller UK gardens. A south or south-west facing wall in full sun is essential for fruiting actinidia; the plants need a long, warm growing season (at least 7 months frost-free) to ripen fruit reliably, which in the UK means the mildest positions in southern and south-west England, London, and similar urban microclimates. For Actinidia kolomikta grown as an ornamental: site on a sheltered south or east-facing wall in full sun; the best pink and white variegation on the male plant develops in the hottest, brightest position. Feed in spring with a balanced fertiliser and again in midsummer with a potassium-rich fertiliser. Water regularly in the first two to three years to establish a deep root system; thereafter established plants need watering only during prolonged dry spells. Prune in late winter (January to February) to keep the plant within bounds and encourage fruiting spurs.

Q: Will actinidia fruit in the UK?

Actinidia can and does fruit in the UK, but reliable fruiting is possible only in the mildest, warmest, most sheltered positions and with the right combination of male and female plants. Actinidia deliciosa (fuzzy kiwi) is the most commonly grown fruiting species but requires a long, warm growing season of 7 to 9 months frost-free and a sheltered south-facing wall in the mildest parts of the UK (coastal and urban southern England, the Channel Islands) to ripen fruit reliably; in most of the UK the growing season is too short and cool for this species to produce ripe fruit consistently, though the plant grows vigorously and may flower without fruiting. Actinidia chinensis (golden kiwi) has similar requirements to Actinidia deliciosa and is generally no easier to fruit in UK conditions. Actinidia arguta (hardy kiwi) is the most reliably fruiting species for UK conditions; the small, smooth-skinned fruits (grape-sized, eaten skin and all, with a sweeter flavour than the large fuzzy kiwi) ripen more quickly and in a shorter, cooler season; the self-fertile cultivar 'Issai' is the best choice for UK fruiting and can produce a worthwhile crop against a warm south or west-facing wall in southern England. All require two or more years to establish before flowering and a minimum of three to four years before fruiting begins. Both male and female plants are needed for all species except self-fertile 'Issai'; plant both at the same time to ensure synchronised flowering.

Actinidia (kiwi vine) includes the fruiting kiwi (Actinidia deliciosa and Actinidia arguta) and the ornamental Actinidia kolomikta, grown for its leaves that develop spectacular pink and white variegation in full sun. All are vigorous climbers for UK warm walls. Drought stress and late frost damage to the tender spring growth are the most common causes of leaf curl; Actinidia kolomikta has the unusual additional problem of attracting cats, which can physically destroy young plants.

Drought stress

Actinidia has large, soft leaves that lose moisture quickly; all species need consistently moist, well-drained, fertile soil and suffer visibly when the root zone dries out in summer, particularly in newly planted specimens without deep roots yet established. Drought stress causes the large leaves to curl inward and develop brown margins; prolonged drought can lead to premature leaf drop and significantly reduced fruit production in fruiting varieties. Wall-base soils dry out particularly quickly against south-facing walls in hot summers, exposing wall-planted actinidia to drought stress even in UK conditions.

What to do

Maintain a deep mulch (10 cm) of composted bark or well-rotted compost around the root zone, extended well beyond the plant's canopy spread, to conserve moisture and feed the roots; this is the single most effective management measure for wall-grown actinidia in UK conditions. Water regularly during the first two to three years after planting; thereafter water during prolonged dry spells (more than 10 to 14 days without significant rainfall). Avoid planting in shallow, freely draining soils directly against a south-facing wall; plant 30 to 45 cm away from the wall base where the soil retains more moisture.

Late frost damage

Actinidia produces its new growth early in spring (March to April in a warm, sheltered position) and the tender emerging shoots and leaves are very vulnerable to late spring frosts below -2 to -3°C; frosted shoots blacken, wilt, and curl, and severely frosted developing flower buds will not set fruit that season. Plants trained on warm south-facing walls break dormancy earlier than open-ground plants and are therefore more frequently caught by late frosts; this is a significant risk in UK springs. The plant recovers from spring frost by producing replacement growth from lower buds, but may not flower or fruit in the affected season.

What to do

Hang two layers of horticultural fleece over the plant on nights when frost is forecast in April and May, particularly when shoots are actively extending; remove the fleece during the day to allow light, pollinating insects, and air circulation. Do not cut back frost-damaged shoots until new growth shows in late spring; the extent of damage can be assessed only after new growth confirms which tissues are alive. In a season when frost has killed the developing flower buds, fruit production will be absent or very poor; the plant will recover fully and flower normally the following year.

Aphids

Aphids colonise the young shoot tips and leaf undersides of actinidia in spring, causing the large, soft leaves to curl and the growing tips to distort; the infestations are typically heaviest on plants in sheltered, enclosed wall positions where natural predator pressure is lower. The vigorous growth of actinidia in a warm position typically outgrows light to moderate aphid infestations within a few weeks as natural predators arrive and the plant grows away from the affected tips. Heavy infestations produce honeydew and attract sooty mould.

What to do

No treatment is needed for light infestations; natural predators and vigorous plant growth resolve the problem. Dislodge aphid colonies from accessible shoots with a strong jet of water. Apply insecticidal soap to young shoot tips and leaf undersides if the infestation is heavy; the spray must contact the aphids directly. Avoid high-nitrogen fertilisers that encourage the very soft, lush growth most attractive to aphids.

Cat damage

Actinidia kolomikta is powerfully attractive to cats, which can cause severe physical damage to young plants: cats roll on them, bite and strip the leaves and stems, scratch the bark, and dig around the roots. Bitten and torn leaves curl and distort; scratched bark can girdle stems causing wilting of the shoots above; root disturbance causes whole-plant wilt. The plant releases actinidine and related compounds (similar to the active ingredient in catnip) when damaged, so cat attention tends to escalate once a plant has been discovered.

What to do

Protect young plants (in the first two to three years) with a cage of chicken wire or mesh around the entire plant until it grows large and robust enough to withstand cat attention without lasting damage; large established plants generally recover from cat damage quickly. Lay spiky material around the base (holly cuttings, bramble prunings, cut pine cones) to deter cats from approaching close to the stems and roots. Commercial cat-repellent granules or sprays applied around the base of the plant may help deter cats. Actinidia deliciosa and Actinidia arguta are less powerfully attractive to cats and rarely suffer the same level of damage as Actinidia kolomikta.

Frequently asked questions

Why are my actinidia leaves curling?

Actinidia leaves curl most commonly because of drought stress (the large, soft leaves curl and develop brown margins when the root zone dries out in summer), late frost damage (tender spring shoots blacken, wilt, and curl after frost in April or May), aphids on young shoot tips and leaf undersides in spring, or physical damage from cats on Actinidia kolomikta. In consistently moist, fertile, sheltered conditions, actinidia is generally trouble-free.

Why do cats like actinidia?

Actinidia kolomikta contains actinidine and related iridoid compounds similar to the active ingredient in catnip; these are released when leaves or stems are damaged and trigger a catnip-like rolling, rubbing, and biting response in cats. Young plants are especially vulnerable as even minor damage releases more scent, escalating cat attention. Protect young plants for the first two to three years with a wire mesh cage; large established plants are generally robust enough to recover from cat attention.

How do I grow actinidia in the UK?

Grow in a sunny, sheltered position (south or west-facing wall) in consistently moist, well-drained, fertile soil. Mulch deeply and water regularly in the first few years. Plant both male and female for fruiting species (except self-fertile Actinidia arguta 'Issai'). Protect spring growth from late frosts with fleece. Prune in late winter to control size and encourage fruiting spurs. Protect young plants from cat damage with a wire cage.

Will actinidia fruit in the UK?

Actinidia arguta (hardy kiwi), especially the self-fertile 'Issai', is the most reliably fruiting species in UK conditions and can produce a good crop on a warm south or west-facing wall in southern England. Actinidia deliciosa (fuzzy kiwi) needs a very long, warm season and is only reliable in the mildest parts of the UK. All species need both a male and female plant (except 'Issai') and three to four years to establish before fruiting begins.