Plant problems

Why Are My Brachypodium Leaves Curling?

Q: Why are my brachypodium leaves curling?

Brachypodium sylvaticum (false brome, slender false brome) and Brachypodium pinnatum (tor grass, chalk false brome) leaves curl, brown at the tips and edges, and the loose, arching clumps lose their characteristic fresh appearance most commonly in UK gardens because of drought or too much sun in a dry position (brachypodium sylvaticum is a native UK woodland edge, hedgerow, and shaded grassland grass that grows naturally in partial to full shade in moderately moist to moist, calcareous, neutral to slightly acid soils; in full sun in a dry, exposed position in summer, the broad, flat, softly hairy leaves of B. sylvaticum curl along their length, brown at the tips and edges, and lose the fresh, lax, arching quality that makes it attractive as an informal ground-cover grass in a shaded UK garden position; Brachypodium pinnatum in contrast is a grass of open chalk and limestone grassland and tolerates full sun better but is still susceptible to leaf curl in very dry conditions on thin, rapidly draining chalk soils in a hot UK summer) or being grown in an excessively warm, dry, exposed position that does not match its preferred habitat (B. sylvaticum is a cool, moist, shaded-habitat grass; B. pinnatum is a calcareous, open-grassland grass; both curl and brown in conditions outside their preferred range). Brachypodium sylvaticum (false brome) is a native UK woodland and hedgerow grass with loose, arching, soft, hairy leaves and a graceful habit; useful as an informal ground-cover grass in partial to full shade in moist soil. Brachypodium pinnatum (tor grass) is a native UK chalk and limestone grassland grass, more sun and drought tolerant, spreading vigorously by rhizomes in calcareous grassland.

Q: Is brachypodium sylvaticum good as a ground cover in shade?

Brachypodium sylvaticum (false brome, slender false brome) can be a useful and naturalistic ground-cover grass in a partially to fully shaded UK garden position in moderately moist soil, particularly in a woodland garden or shaded border context where a grass with a softer, more relaxed habit than the tidier carex and luzula cultivars is wanted. Its soft, hairy, bright to mid-green leaves and graceful, loosely arching habit give it a natural, informal character that blends well with the kind of woodland perennials and bulbs (bluebells, foxgloves, wood anemones, ferns) used in a naturalistic shaded garden border. As a UK native plant, it supports a range of UK grassland and woodland specialist invertebrates, including the species-specific brachypodium-feeding caterpillars of several UK woodland and grassland Lepidoptera (moths and butterflies). However, in a formal or carefully managed ornamental garden context, B. sylvaticum may be considered insufficiently tidy: it self-seeds readily, can spread substantially in the right conditions, and the individual plants become rather open and informal in habit rather than forming neat, compact clumps. In a wild garden, a naturalised meadow fringe, or a deliberately informal woodland garden, self-seeding is an advantage; in a formal border where control is important, it can become a significant management task. The cultivar Brachypodium sylvaticum is not commonly sold as a named garden selection in the way that carex or festuca cultivars are; it is used primarily in its straight species form in naturalistic or conservation planting contexts.

Q: Is brachypodium native to the UK?

Yes, both Brachypodium sylvaticum (false brome, slender false brome) and Brachypodium pinnatum (tor grass, chalk false brome) are native UK grasses. Brachypodium sylvaticum is a widespread native grass of woodland edges, hedgerow banks, shaded grassland, road verges, and semi-shaded scrub habitats across England, Wales, and parts of Scotland and Ireland; it is the more shade-tolerant of the two species and characteristically grows in the soft, dappled light of woodland margins and hedgerow bases, where its loosely arching, soft, hairy leaves and graceful habit are at their most attractive. Brachypodium pinnatum is a native UK grass of chalk and limestone grassland, predominantly in southern and central England (south of a line from the Severn to the Wash, broadly); it is not native to Scotland or Ireland, though it may occur as an introduction in some parts of Wales. There is also a third UK native brachypodium, Brachypodium rupestre (heath false brome), which is sometimes treated as a subspecies of B. pinnatum and occurs in somewhat more acidic grassland and heath habitats in parts of western and northern Britain; the taxonomy of the B. pinnatum/rupestre complex is not fully resolved. A fourth species, Brachypodium distachyon (stiff brome, annual wall grass), occurs very rarely in the UK as a casual introduction in a few warm, dry, southern English habitats, but is not a true UK native. Brachypodium sylvaticum and B. pinnatum are both used in UK grassland restoration and native wildflower seed mixtures for the appropriate habitat types.

Brachypodium sylvaticum (false brome) is a native UK woodland and hedgerow grass with soft, hairy, loosely arching leaves; useful as naturalistic ground cover in partial to full shade. B. pinnatum (tor grass) is a native of UK chalk and limestone grassland. Drought and full sun cause leaf curl in B. sylvaticum; B. pinnatum is more sun-tolerant but can still curl in very dry conditions on thin chalk soils.

Drought and too much sun

B. sylvaticum is a cool, moist, shaded-habitat grass; in full sun in dry soil in summer, the broad, soft, hairy leaves curl along their length and brown at the tips and edges, losing the fresh, lax, arching quality that makes it attractive as informal ground cover. Even in partial shade, if the soil dries out significantly in summer, leaf curl develops. B. pinnatum tolerates full sun better but curls in very dry conditions on thin chalk soils.

What to do

Grow B. sylvaticum in partial to full shade in moderately moist soil; it is a woodland and hedgerow grass, not a sunny border grass. Mulch with leaf mould to retain moisture and match the woodland soil conditions it prefers. Water in dry spells in summer to maintain the fresh, lax leaf quality. For a sunny, dry position, B. pinnatum is more suitable but is very vigorous and spreading; in most garden contexts a species with less invasive potential is preferable in a formal planting.

Wrong position for the species

Both brachypodium species will show poor performance and leaf curl if grown in conditions that do not match their preferred habitat: B. sylvaticum in dry, sunny, exposed positions; B. pinnatum in very shaded, moist positions or acid soils (it is a calcareous grassland specialist). The key is to match the species to its natural habitat type.

What to do

Use B. sylvaticum in shaded, moist, neutral to calcareous soil in a woodland or hedgerow garden context; use B. pinnatum only in open, sunny, chalky or calcareous soil where its vigour and spreading habit can be managed. In a formal garden, consider whether either species is appropriate; B. sylvaticum self-seeds freely and B. pinnatum is rhizomatously invasive in calcareous conditions. Both are better suited to naturalistic, conservation, or restoration planting than to a tightly managed ornamental border.

Invasive spread (B. pinnatum)

Brachypodium pinnatum (tor grass) spreads vigorously by rhizomes in chalk and limestone grassland and can be very difficult to control once established in a calcareous soil; this is the primary management consideration with this species in a garden or conservation context. It is a recognised conservation problem on UK chalk downland where it suppresses wildflower-rich swards.

What to do

In a garden context, do not plant B. pinnatum in a calcareous border where control is important; once established, removal requires consistent effort over several seasons. In a chalk downland or limestone grassland conservation context, control through intensive autumn and winter sheep grazing, late summer cutting, or localised herbicide treatment followed by re-seeding is the standard management approach. B. sylvaticum also self-seeds freely in the right conditions but is less aggressively rhizomatous and easier to manage than B. pinnatum.

Frequently asked questions

Why are my brachypodium leaves curling?

Brachypodium leaves curl most commonly because of drought and too much sun in a dry position (B. sylvaticum is a cool, moist, shaded woodland grass; grow in partial to full shade in moist soil; mulch with leaf mould; water in dry spells), wrong position for the species (B. sylvaticum needs shade and moisture; B. pinnatum needs open, sunny, calcareous conditions; match the species to its natural habitat), or in a garden context, B. pinnatum may spread too vigorously by rhizomes to be appropriate (B. pinnatum is a conservation problem on chalk grassland; very difficult to control once established). B. sylvaticum is the more garden-suitable of the two species.

Is brachypodium sylvaticum good as a ground cover in shade?

Yes in the right position: partial to full shade in moderately moist, neutral to calcareous soil. Soft, hairy, loosely arching leaves give a natural, informal character suited to woodland gardens; blends well with bluebells, foxgloves, ferns, and wood anemones. Self-seeds readily in good conditions; an advantage in a wild garden or informal planting, a management task in a formal border. Not commonly sold as named ornamental cultivars; used primarily in its species form for naturalistic and conservation planting.

Is brachypodium pinnatum a problem in UK chalk grassland?

Yes; a native UK grass but a serious conservation problem on UK chalk and limestone grassland, expanding dramatically since the 1970s to form dense mats that suppress species-rich wildflower swards. Expansion linked to loss of traditional sheep and rabbit grazing, atmospheric nitrogen deposition, and climate warming. Management through intensive autumn and winter sheep grazing, late summer cutting, or localised herbicide followed by re-seeding. Overall invertebrate and plant diversity in B. pinnatum-dominated swards is much lower than in well-managed short chalk grassland.

Is brachypodium native to the UK?

Yes; B. sylvaticum (false brome) is a widespread native of woodland edges, hedgerow banks, and shaded grassland across England, Wales, and parts of Scotland and Ireland. B. pinnatum (tor grass) is a native of chalk and limestone grassland predominantly in southern and central England. A third species, B. rupestre (heath false brome), occurs in more acidic habitats in parts of western and northern Britain. Both B. sylvaticum and B. pinnatum are used in UK grassland restoration and native wildflower seed mixtures for the appropriate habitat types.