Plant problems

Why Are My Lindera Leaves Curling?

Q: Why are my lindera leaves curling?

Lindera leaves curl most commonly in the UK because of drought stress, late spring frost damage to young growth, wrong soil conditions, or aphid infestation on the young shoot tips. The two species most likely to be encountered in UK gardens are Lindera benzoin (spicebush), a deciduous North American shrub grown for its aromatic leaves, bark, and berries with small yellow flowers before the leaves in spring and bright red berries on female plants in autumn; and Lindera obtusiloba (Japanese spicebush), a deciduous Asian shrub with attractive three-lobed leaves that colour well in autumn. Both grow naturally in moist, acid to neutral, woodland soils and share similar cultural requirements. Drought stress is the most common cause of leaf curl: Lindera benzoin grows naturally in the moist understorey of North American deciduous woodland, often along stream banks, and the large, soft leaves curl and develop brown margins when the root zone dries out in summer, particularly in newly planted specimens before deep roots are established. Late spring frost damage affects the young, soft leaves as they expand in April and May: frosted leaves curl, brown at the tips, and may fail to expand normally. The large, soft, pleasantly aromatic leaves of Lindera benzoin are attractive to aphids in spring; aphid colonisation of the young shoot tips causes the leaves to curl around the colonies.

Q: What is lindera used for?

Lindera benzoin (spicebush) has a long history of use by Native American peoples and early European colonists in North America for food, medicine, and spice; all parts of the plant are aromatic with a complex, spicy-citrus fragrance. The dried berries of Lindera benzoin were used as a spice by early settlers as a substitute for allspice (Pimenta dioica), to which the flavour bears a resemblance; the berries ripen in late summer to early autumn and are highly aromatic when dried; they contain a high proportion of lauric acid and have a warming, spicy flavour used in soups, stews, and baked goods. The bark and leaves have been used in traditional herbal medicine for a range of complaints; the plant has aromatic properties similar to those of bay (Laurus nobilis) and spices of the laurel family, to which it is related. Lindera obtusiloba (Japanese spicebush) is grown primarily as an ornamental in UK gardens, particularly for the striking three-lobed leaves that turn vivid yellow in autumn, and for the small, star-shaped yellow flowers produced on bare stems in February to March before the leaves; it is an attractive specimen shrub for woodland garden conditions where its early flowers and good autumn colour are assets. Both species are edible: the berries, bark, and leaves can be used as spices and flavourings, though Lindera benzoin is the species with the established culinary tradition; Lindera obtusiloba berries are similarly aromatic and edible. In the UK garden context, both species are grown primarily as ornamental woodland shrubs.

Q: How do I grow lindera in the UK?

Lindera benzoin and Lindera obtusiloba both grow well in UK conditions in acid to neutral, consistently moist but well-drained, humus-rich soil in partial shade or dappled sunlight. The conditions needed are similar to those that suit enkianthus, fothergilla, and witch hazel: a woodland garden setting with a leafy, moisture-retentive but not waterlogged soil and shelter from drying east and north winds. Lindera benzoin in particular prefers moist conditions and grows naturally along stream banks; it is very well suited to waterside planting or to the moist margins of a woodland garden where the soil stays consistently damp. Full sun is tolerated if the soil is consistently moist, but the large, thin-textured leaves scorch in strong sun on dry soils. In the UK, Lindera benzoin is dioecious (male and female flowers on separate plants); to obtain the red berries that are one of the ornamental features of female plants, both a male and a female plant need to be grown. Lindera obtusiloba produces its most abundant autumn colour in full sun to light partial shade with moist, fertile, acid soil; the best specimens develop in conditions similar to those that produce outstanding autumn colour in enkianthus and fothergilla. Both species need minimal pruning; remove dead, damaged, or crossing branches in early spring. Lindera benzoin spreads slowly by suckering to form a colony in ideal conditions; suckers can be removed to maintain a single-stemmed specimen or left to colonise naturally.

Q: When does lindera flower?

Lindera obtusiloba (Japanese spicebush) flowers in February and March in the UK, producing clusters of small, star-shaped, bright yellow flowers on bare stems before the leaves emerge; the display is similar in timing and style to witch hazel (Hamamelis) and is one of the earliest flowering shrubs of the calendar year. The flowers are fragrant and make a cheerful display in late winter; they are attractive to early bees on warm days in February. The three-lobed, mid-green leaves follow the flowers and develop attractive yellow, orange, and occasionally red autumn tones in October and November. Lindera benzoin (spicebush) also flowers before the leaves, producing clusters of tiny yellow-green flowers in March and April on bare stems; the flowers are smaller and less showy than those of Lindera obtusiloba, but the fragrant foliage, bright red berries on female plants in autumn, and good yellow autumn leaf colour make it a plant with four-season interest. Lindera benzoin is dioecious: male plants produce only pollen, female plants produce only berries (no berries without a male plant nearby for pollination). Both species are hardy in the UK; Lindera benzoin is fully hardy to at least -20°C; Lindera obtusiloba is hardy to about -15 to -20°C. Both are suitable for UK woodland gardens where witch hazel, enkianthus, and hamamelis succeed.

Lindera (spicebush) includes Lindera benzoin from eastern North America and Lindera obtusiloba from East Asia, both grown in UK woodland gardens for their aromatic foliage, early spring flowers, and autumn colour. Both prefer moist, acid to neutral, humus-rich soil in partial shade; drought stress and late frost damage to the large, soft spring leaves are the most common causes of leaf curl in UK garden conditions.

Drought stress

Lindera benzoin grows naturally along stream banks and in moist woodland understorey in eastern North America; the large, soft, aromatic leaves lose moisture quickly and curl inward with brown margins when the root zone dries out during dry UK summers, particularly in freely draining soils and in newly planted specimens without a deep root system yet established. Lindera obtusiloba is somewhat more drought-tolerant but similarly benefits from consistently moist, humus-rich soil. Both species show drought stress most visibly in mid to late summer after prolonged dry spells.

What to do

Maintain a deep mulch (8 to 10 cm) of composted bark or leaf mould around the root zone to conserve moisture; this is the most effective long-term moisture management measure for lindera. Water during dry spells in the first two to three years after planting; established plants in well-mulched, moisture-retentive soil rarely need supplementary watering in most UK gardens. Choose a position with some afternoon shade to reduce moisture demand and prevent leaf scorch on the thin-textured leaves.

Late frost damage

The soft, young leaves of lindera emerging in April and May are vulnerable to late spring frosts; frosted leaves curl, brown at the tips and margins, and may fail to expand fully. The early flowers of Lindera obtusiloba (produced in February to March on bare stems) can also be damaged by late frosts, turning brown and shrivelling. Both species are very hardy when dormant but the tender new growth is vulnerable to temperatures below about -2 to -3°C. The plant recovers from spring frost damage by producing replacement growth from unaffected buds later in spring.

What to do

Avoid planting in frost pockets where cold air collects on still spring nights; a slight slope or an open position under deciduous trees provides better frost drainage than a low-lying hollow. If a frost is forecast when leaves or flowers are expanding, cover smaller plants with horticultural fleece overnight. Cut frost-damaged shoot tips back to healthy buds in late May when replacement growth confirms the extent of damage.

Aphids

Aphids can colonise the young, expanding shoot tips of lindera in spring; the new leaves curl around the aphid colonies and may fail to expand normally. Infestations on lindera are typically light and short-lived; natural predators (ladybirds, lacewings) arrive quickly, and the strongly aromatic nature of the foliage may reduce the plant's appeal to aphids compared with less fragrant species. The problem is most visible in April and May on the first flush of spring growth.

What to do

No treatment is usually needed; natural predators and the plant's vigorous growth control light infestations within a few weeks. Pinch off heavily colonised shoot tips to reduce populations quickly. Apply insecticidal soap spray to young growth if the infestation is heavy and the plant is small; the spray must contact the aphids directly. Avoid high-nitrogen feeding that promotes the soft, lush growth most attractive to aphids.

Soil pH and conditions

Lindera grows best in acid to neutral soil (pH 5.0 to 6.5); in alkaline or strongly calcareous soils, the plant may show interveinal yellowing of new leaves similar to the lime-induced chlorosis seen in ericaceous plants, though lindera is generally somewhat more tolerant of near-neutral pH than strictly ericaceous plants such as rhododendrons. Waterlogged soil is damaging over winter; lindera needs consistently moist but aerated soil and will not tolerate prolonged root saturation.

What to do

Test soil pH before planting; the ideal range is 5.0 to 6.5. Incorporate composted leaf mould or acidic organic matter to improve moisture retention and gently lower pH in near-neutral soils. Ensure the planting position drains adequately; lindera needs consistent moisture, not standing water. Apply chelated iron if chlorosis develops in marginally alkaline conditions as a temporary measure while soil conditions are improved.

Frequently asked questions

Why are my lindera leaves curling?

Lindera leaves curl most commonly because of drought stress (the large, thin leaves curl and brown at the margins when the root zone dries out in summer), late frost damage to the soft spring growth, aphids on young shoot tips in spring, or marginally unsuitable soil pH. Both Lindera benzoin and Lindera obtusiloba are trouble-free in the correct moist, acid, sheltered woodland conditions and rarely suffer serious problems.

What is lindera used for?

Lindera benzoin (spicebush) berries are used as a spice similar to allspice; the dried berries, bark, and leaves are all aromatic with a warming, spicy-citrus flavour. Lindera obtusiloba is grown primarily as an ornamental for its February to March yellow flowers on bare stems, three-lobed aromatic leaves, and vivid yellow autumn colour. Both species have a long history of culinary and medicinal use in their native regions.

How do I grow lindera in the UK?

Grow in acid to neutral soil (pH 5.0 to 6.5), in partial shade or dappled sunlight, in consistently moist but well-drained humus-rich conditions; mulch deeply with bark or leaf mould. Conditions similar to witch hazel and enkianthus suit both species. Lindera benzoin prefers reliably moist positions and grows well near water. To get berries on Lindera benzoin, grow both a male and female plant (the species is dioecious).

When does lindera flower?

Lindera obtusiloba flowers in February to March on bare stems with clusters of small star-shaped yellow flowers; one of the earliest flowering shrubs of the year. Lindera benzoin flowers in March to April before the leaves with tiny yellow-green clusters, less showy but fragrant. Both are followed by good autumn foliage colour; Lindera benzoin also produces red berries on female plants in autumn.