Plant problems

Why Are My Drimys Leaves Curling?

Q: Why are my drimys leaves curling?

Drimys winteri (winter's bark) leaves curl and drop most commonly in UK gardens because of cold damage in hard winters (drimys is only moderately hardy and the large, glossy, elliptic, aromatic leaves curl and drop in hard frost below about -10°C in exposed conditions), drought stress in summer (the large, leathery leaves curl inward when the root zone dries out), or cold, drying wind in winter (desiccation from cold winter wind strips moisture from the evergreen leaves faster than the frozen roots can replace it, causing the leaves to curl and brown at the margins). Drimys winteri (Winter's bark, named after Captain William Winter who collected it from Tierra del Fuego in 1578 and used its bark medicinally on the voyage) is a large, upright, evergreen shrub or small tree from the cool, moist forests of Chile and Argentina, grown in UK gardens for its large, glossy, aromatic, blue-green leaves and its clusters of fragrant white jasmine-like flowers produced in April to May; the flowers have a sweet, almost tropical scent and are produced in abundance on mature plants. The aromatic bark, which has a pungent, spicy scent when scratched or rubbed, was historically used by sailors as a substitute for pepper and as a source of vitamin C; the genus is named in honour of Captain Winter. Drimys winteri is a plant of the Valdivian temperate rainforest and similar cool, moist, southern hemisphere forest habitats; like desfontainia, mitraria, and berberidopsis, it performs best in the moist, acid, sheltered gardens of western and northern UK, particularly in Scotland and south-west England.

Q: How do I grow drimys in the UK?

Drimys winteri grows best in a sheltered position with protection from cold wind (particularly cold north and east wind in winter), in consistently moist, moderately fertile, well-drained, acid to neutral soil. Shelter from wind is at least as important as temperature for UK success; position against a south or west-facing wall, within a sheltered woodland garden, or in a valley position where cold air drainage prevents frost pockets. Full sun to light shade is acceptable; the plant flowers more prolifically in a position with reasonable light. Add leaf mould or composted bark to improve moisture retention and soil structure. Mulch annually with composted bark to maintain soil moisture and slightly acid pH; drimys does not thrive in alkaline soil, though it is not as strictly acid-requiring as desfontainia or mitraria. Water in its first season after planting; established plants in well-prepared, mulched soil rarely need supplementary watering in average UK summer conditions. Prune minimally; drimys does not require regular pruning and does not regenerate reliably from old, bare wood. Remove any dead or frost-damaged growth in spring. The plant is slow to establish in its first two to three years but grows more strongly once settled in its position.

Q: Why does drimys smell?

Drimys winteri is strongly aromatic throughout the plant; the leaves, bark, and flowers all produce distinctive scents that are a notable feature of the plant at close range. The bark has a pungent, spicy, pepper-like scent when scratched or rubbed; this aromatic bark was historically used by Captain Winter's sailors in 1578 as a substitute for pepper and as a remedy for scurvy (the bark contains vitamin C and other compounds); the plant's common name 'Winter's bark' and its scientific epithet 'winteri' both commemorate Captain Winter and this voyage. The leaves have a similar aromatic quality when crushed; the scent is clean, spicy, and slightly medicinal. The white flowers, produced in clusters in April to May, have a much sweeter, jasmine-like fragrance that is pleasant rather than pungent and can be detected several metres from the plant on still, warm spring days; the flower scent is the most agreeable of the plant's three distinct fragrance characteristics and is the principal ornamental quality of the flowering display. The aromatic compounds in the bark and leaves are believed to function as a defence against herbivory and pathogens in the plant's native southern hemisphere forest habitat.

Drimys winteri (Winter's bark) is a large, upright, fragrant evergreen shrub or small tree from the cool forests of southern Chile and Argentina, grown for its large blue-green aromatic leaves and clusters of sweet-scented white flowers in April to May. Hardy to about -10 to -15°C (depending on form) in sheltered conditions, it performs best in western UK gardens. Cold wind causes more damage than frost alone; shelter is the most critical requirement.

Cold wind and frost

Cold, drying wind in winter is the most common cause of leaf curl and browning in drimys in UK gardens; the large, evergreen leaves lose moisture through transpiration faster than frozen roots can replace it, causing the leaf margins to brown and curl. This wind desiccation damage is distinct from (and often worse than) direct frost damage. Hard frost below about -10°C in an exposed position also curls and drops the leaves. The hardiest form, Drimys winteri var. andina, is significantly more frost-tolerant but still benefits strongly from shelter against cold wind.

What to do

Provide shelter from north and east wind; a south or west-facing wall, sheltered woodland position, or valley location all reduce wind exposure significantly. Wrap young plants in fleece from November to March in exposed positions. Do not cut back until April; surviving buds may be concealed in apparently bare stems. In very cold areas, grow Drimys winteri var. andina, the hardiest form.

Drought stress

The large, leathery, blue-green leaves of drimys curl inward when the root zone dries out in summer; the plant comes from the Valdivian temperate rainforest, one of the world's most consistently moist environments, and is not drought-adapted. Container-grown plants are most vulnerable; drimys is best grown in the ground where the root system can access consistent soil moisture. In average UK summer conditions, established, mulched plants in the ground rarely suffer significant drought stress.

What to do

Mulch deeply (10 cm) with composted bark each spring to retain soil moisture. Water newly planted specimens consistently in their first two to three years until well established. Water in-ground plants during prolonged summer dry spells. Container-grown plants need regular watering in summer; use a large container to provide greater root volume.

Waterlogging

Although drimys prefers consistently moist conditions, it does not tolerate waterlogged or permanently saturated soil; the roots rot in anaerobic, saturated conditions and the plant declines progressively. The ideal soil is moist but freely draining with good aeration throughout the root zone. In heavy clay soils, the combination of winter waterlogging and cold is particularly damaging; good drainage before planting is essential in clay-heavy gardens.

What to do

Plant in well-drained, moisture-retentive soil; add leaf mould and coarse grit to clay soils. Avoid low-lying positions where water collects in winter. The ideal soil is similar to that for rhododendrons and camellias: acid to neutral, moist but freely draining, with good aeration and high organic matter content.

Frequently asked questions

Why are my drimys leaves curling?

Drimys leaves curl most commonly because of cold wind desiccation in winter (cold, drying wind causes the large evergreen leaves to curl and brown at the margins; this is often worse than direct frost damage; shelter is essential), drought stress in summer (mulch deeply and water established plants during dry spells), or frost below -10°C in exposed conditions (the hardy var. andina tolerates more cold; wrap young plants in fleece). Shelter from cold wind is more important than absolute winter temperature for UK success.

Is drimys hardy in the UK?

Drimys winteri var. andina is the hardiest form, surviving to about -15°C in sheltered conditions and reliably perennial throughout most of the UK. Typical Drimys winteri is hardy to about -10 to -12°C. Both forms are best in sheltered, western and northern UK gardens where cold wind is minimised; in exposed, eastern positions they are less reliable. Western Scotland in sheltered positions produces spectacular large specimens over many decades.

How do I grow drimys in the UK?

Grow in a sheltered position protected from cold north and east wind; against a south or west-facing wall or in a sheltered woodland garden are ideal. Moist, acid to neutral, well-drained soil; mulch annually with composted bark. Full sun to light shade. Water in the first season; established plants need watering only in prolonged dry spells. Prune minimally. The fragrant white flowers in April to May are the principal ornamental feature of mature plants.

Why does drimys smell?

Drimys winteri is aromatic throughout: the bark has a pungent, spicy, pepper-like scent (used medicinally by Captain Winter's sailors in 1578, giving the plant its common and scientific names); the leaves produce a similar spicy scent when crushed; and the white flowers in April to May produce a sweet, jasmine-like fragrance detectable several metres from the plant. The flower fragrance is the most agreeable and is the primary ornamental quality of the spring flowering display.