Plant problems

Why Are My Ophiopogon Leaves Curling?

Q: Why are my ophiopogon leaves curling?

Ophiopogon (mondo grass or lilyturf) leaves curl and brown at the tips most commonly in UK cultivation because of drought stress (ophiopogon prefers consistently moist, humus-rich soil; the narrow, arching, strap-like leaves curl along their length and develop brown tips when the root zone dries out, particularly in the first one to two years after planting before the root system has established fully; established ophiopogon in a reasonably moist UK soil is moderately drought-tolerant, but container-grown plants and those in light, sandy soils are consistently vulnerable), too much direct sun in a hot position (while ophiopogon japonica tolerates full sun in UK conditions, O. planiscapus 'Nigrescens' and some other cultivars perform better in partial shade; in a hot, sunny, south-facing position, the leaves of shade-preferring cultivars bleach, curl, and develop brown tips from heat and desiccation stress), or cold and frost damage in hard UK winters (ophiopogon is generally hardy in most of the UK but the narrow leaves curl and develop brown tips after sustained cold below about -10 to -15°C or after cold, desiccating winter winds in an exposed position; the foliage is evergreen and provides year-round interest, but winter damage is cosmetic and the plants recover fully in spring). Ophiopogon is a genus of around 50 to 60 species of evergreen, clump-forming perennials in the asparagus family (Asparagaceae) from East and South-East Asia; the most commonly grown species in UK gardens are Ophiopogon planiscapus (black mondo grass, especially the cultivar 'Nigrescens' with its striking black-purple leaves, a unique colour effect in the plant world) and Ophiopogon japonicus (dwarf mondo grass, with narrow, dark green leaves used as a dense, low-maintenance ground cover).

Q: Is ophiopogon hardy in the UK?

Ophiopogon planiscapus 'Nigrescens' (black mondo grass) and Ophiopogon japonicus (dwarf mondo grass) are both reliably hardy in most of the UK; they tolerate temperatures to approximately -12 to -15°C in well-drained conditions and are perennial in virtually all UK gardens except the most exposed upland or continental-climate sites. The leaves may be damaged by the most severe UK winters (browning and curling in sustained frost below about -10°C or in cold, desiccating winds), but the plants recover fully from the crown in spring and produce fresh growth from April. In mild UK winters the foliage remains entirely undamaged and provides attractive year-round ground cover. Ophiopogon is essentially trouble-free in terms of cold hardiness in the UK climate; the challenges are more about moisture, light, and competition from weeds (particularly grass, which is almost invisible when growing through a clump of dwarf mondo grass) than cold hardiness.

Q: How do I grow ophiopogon in the UK?

Ophiopogon grows best in a position with partial shade to dappled light in moist, humus-rich, well-drained, neutral to slightly acid soil; it performs particularly well under deciduous trees or in the shade of shrub borders where the soil is enriched with leaf fall over time. Ophiopogon planiscapus 'Nigrescens' (black mondo grass) is most effective planted as a ground cover or as an accent plant in a gravel or pebble garden where the black leaves contrast dramatically with a pale stone mulch. Plant from spring to early autumn; space plants 15 to 20 cm apart for ground cover use. Water consistently in the first growing season to establish the root system; once established, ophiopogon in a reasonable UK garden soil needs little supplementary watering except in prolonged drought. Top-dress annually with leaf mould or fine composted bark to maintain moisture retention and soil organic matter. Divide congested clumps every three to four years in spring to maintain vigour and propagate additional plants; ophiopogon divides easily with a sharp spade or hand fork. Remove any brown or damaged leaves in early spring before new growth begins to maintain a tidy appearance. Feed lightly with a balanced general-purpose fertiliser in spring; avoid over-feeding, which produces lush growth that is less drought-tolerant.

Q: What is the difference between ophiopogon and liriope?

Ophiopogon and Liriope are closely related evergreen, clump-forming perennials in the same family (Asparagaceae) that look very similar in leaf form and habit; the easiest way to tell them apart in the garden is by their flowers and berries. Liriope (lilyturf) produces upright, dense spikes of small flowers that stand erect above the leaves and are highly visible from late summer to autumn; ophiopogon produces shorter, less conspicuous flower spikes that are often hidden within or below the leaf canopy and are less showy. Liriope berries are typically black or dark purple and produced in clusters on the upright spike; ophiopogon berries are brilliant blue (O. planiscapus, O. japonicus) or white, and are particularly striking in 'Nigrescens' where vivid blue berries contrast with the black leaves. In terms of leaf: ophiopogon leaves are typically narrower and more grass-like than liriope; liriope leaves are broader and more strap-like, making liriope look more like a small iris or agapanthus in foliage. Both are used as low-maintenance ground cover in similar conditions (partial shade, moist, humus-rich soil), and both are reliable, unfussy performers in UK gardens. In common usage, both are sometimes called 'lilyturf' or 'mondo grass', adding to the confusion.

Ophiopogon (mondo grass) is an evergreen, clump-forming perennial from East Asia with narrow, arching, strap-like leaves used as ground cover or accent planting in UK gardens. Ophiopogon planiscapus 'Nigrescens' (black mondo grass) is the most distinctive cultivar, with unique black-purple leaves and vivid blue berries. Drought in the first season and excessive sun on shade-preferring cultivars are the primary causes of leaf curl.

Drought stress

Drought is the most common cause of ophiopogon leaf curl, particularly in newly planted specimens that have not yet developed a deep root system; the narrow leaves curl along their length and brown at the tips when the root zone dries out. Container-grown ophiopogon and plants in light, sandy soils or hot, south-facing positions are most vulnerable. Established ophiopogon in a moist, shaded UK border position is moderately drought-tolerant, but drought in the first two growing seasons sets back establishment significantly.

What to do

Water consistently through the first full growing season after planting; do not allow newly planted ophiopogon to dry out from April to October. Apply a 5 cm leaf mould or fine bark mulch over the root zone every spring to retain moisture and maintain the humus-rich soil conditions ophiopogon prefers. Established plants need supplementary watering only during prolonged dry spells in summer; check soil moisture at 5 cm depth before watering.

Too much sun

Ophiopogon planiscapus 'Nigrescens' and similar shade-preferring cultivars develop bleached, curling, brown-tipped leaves when grown in a hot, exposed, south-facing position in full summer sun; the black leaf colour fades toward bronze and the leaves curl as the plant struggles in conditions beyond its preferred range. The striking black colour of 'Nigrescens' is best maintained in partial shade; in very deep shade the colour also fades slightly to dark green, but the plant grows well.

What to do

Position shade-preferring ophiopogon cultivars in dappled or partial shade; a position receiving morning sun and afternoon shade is ideal in most UK gardens. Move container-grown specimens to a shadier position if bleaching or leaf curl develops in a sunny position. O. japonicus (dwarf mondo grass) is more sun-tolerant and can be grown in full sun in UK conditions if the soil is adequately moist.

Cold and frost damage

In very hard UK winters with sustained temperatures below -10 to -12°C or in exposed positions with cold, desiccating winter winds, ophiopogon leaves curl, brown at the tips, and may die back partially. The damage is cosmetic rather than fatal; the crown and root system of established ophiopogon survive temperatures that damage or kill the foliage, and new growth emerges from the crown in April. In most UK winters, ophiopogon foliage remains undamaged and the plant provides reliable evergreen winter interest.

What to do

Remove damaged leaves in early spring before new growth begins to maintain a tidy appearance; cut back to the base with scissors or shears. In very exposed positions, a light covering of horticultural fleece on the coldest nights reduces wind desiccation of the leaves. In most UK gardens, no winter protection is needed; trust the plant's hardiness and simply tidy in spring.

Frequently asked questions

Why are my ophiopogon leaves curling?

Ophiopogon leaves curl most commonly because of drought stress (particularly in the first year; narrow leaves curl and tip-brown when roots dry out; water consistently through establishment; mulch with leaf mould), too much sun on shade-preferring cultivars (bleaching and curl in hot, south-facing positions; move to dappled or partial shade), or cold and wind in severe winters (tip browning and curl below -10°C; cosmetic only; tidy in spring). Drought in the first season and wrong light levels are the most frequent causes.

Is ophiopogon hardy in the UK?

Ophiopogon planiscapus and O. japonicus are reliably hardy in most of the UK, tolerating temperatures to approximately -12 to -15°C. Foliage may brown in very severe winters but the crown and roots survive and the plant regrows in spring. In mild UK winters the foliage remains undamaged and provides attractive year-round ground cover. No winter protection is needed in most UK gardens; the main challenges are moisture and light level rather than cold hardiness.

How do I grow ophiopogon in the UK?

Grow in partial shade to dappled light in moist, humus-rich, well-drained, neutral to slightly acid soil. Mulch annually with leaf mould. Water consistently in the first growing season; established plants need supplementary watering only in prolonged drought. Divide congested clumps every three to four years in spring. Remove brown or damaged leaves in early spring. Feed lightly with balanced fertiliser in spring. Plant 15 to 20 cm apart for ground cover use.

What is the difference between ophiopogon and liriope?

Liriope (lilyturf) has broader leaves and showy, upright, visible flower spikes from late summer; ophiopogon has narrower, more grass-like leaves and less conspicuous flower spikes often hidden within the foliage. Ophiopogon berries are brilliant blue or white (striking in black-leaved 'Nigrescens'); liriope berries are dark purple or black. Both are used as low-maintenance ground cover in partial shade in moist, humus-rich soil. Both are sometimes called 'lilyturf' or 'mondo grass', which adds to garden-centre confusion.