Plant problems

Why Are My Polypogon Leaves Curling?

Q: How do I grow polypogon monspeliensis ornamentally in the UK?

Polypogon monspeliensis (annual beard grass) can be grown in a UK garden as an ornamental annual grass, valued for the softness, silkiness, and fine-textured, beard-like quality of its flower panicles, which are produced from June to August and have a tactile quality that few other grasses match. From seed: sow directly in a prepared seedbed in April to May; the seed is very fine and should be surface sown and watered in gently; thin seedlings to 10 to 15 cm apart; alternatively, sow in modules under glass in March and plant out after last frost. Alternatively, polypogon readily self-seeds in suitable open, damp, disturbed ground conditions and can naturalise in a damp garden without annual intervention if allowed to set seed. Position: an open, sunny to lightly shaded position in moist to moderately moist, open, well-drained (not waterlogged) soil; polypogon prefers a moist, open, sandy or silty soil and does not perform well in very dry, compacted, or heavy clay conditions; a moist, open, sunny border position, the edge of a garden pond in open ground, or a moist raised bed are all suitable. Watering: keep consistently moist through the growing season, particularly in July and August when the flower heads are developing; drought curl of the soft leaves significantly detracts from the ornamental quality of the panicles, which are softest and most silky when the plant is well-watered. Harvest: for cut or dried flowers, harvest the panicles when they are at the freshest, most fully developed, soft green stage; the panicles dry well and retain much of their silky softness when dried at this early stage; if left to fully ripen on the plant, the awns and seeds begin to shatter and the panicle becomes less attractive as a dried flower.

Q: What is the difference between polypogon and phleum?

Polypogon (beard grasses) and Phleum (cat's-tail grasses, timothy) are two genera of grasses that both produce dense, spike-like (though botanically panicle-like) flower heads that superficially resemble each other in the field; they can be confused by non-specialist UK botanists, particularly when seen from a distance or in a photograph, but differ in several important ways: Awn character: Polypogon species have very prominent, long, spreading, fine awns on the lemma and glume, giving the whole head a very distinctly bearded, bristly, or silky-hairy appearance; Phleum species have short awns (or no obvious awn) and the heads are smooth-surfaced and cylindrical, not bearded. Head shape: Polypogon heads tend to be more loosely cylindrical, softer, and silkier in appearance; Phleum heads (particularly Phleum pratense, timothy) are very dense, very tightly cylindrical, and firm — the characteristic cat's-tail shape that gives Phleum its common name. Touch: Polypogon heads feel very soft and silky (the fine awns give a fur-like or beard-like feel); Phleum heads feel firm and dense, more like a compact cylindrical brush. Annual vs perennial: Polypogon monspeliensis (the main UK species) is an annual; Phleum pratense (timothy) is a perennial. Habitat: Polypogon is found in open, wet, disturbed, often saline or brackish habitats in the UK; Phleum pratense is ubiquitous in grasslands, meadows, and pastures throughout the UK. UK distribution: Phleum pratense is extremely common throughout the UK; Polypogon monspeliensis is scarcer, primarily in coastal and lowland southern UK.

Q: Is polypogon monspeliensis native to the UK?

Polypogon monspeliensis (annual beard grass) has a complicated native versus introduced status in the UK and is classified differently by different authorities and in different parts of its UK range. The species is native to the Mediterranean region, the Middle East, south-west Asia, and parts of Africa, and has been introduced to many other parts of the world including North America, South Africa, Australia, and New Zealand, where it is often naturalised and in some contexts considered an invasive species of irrigated agricultural land and wet disturbed ground. In the UK, Polypogon monspeliensis is generally considered to have been introduced and naturalised (not native) in much of its UK occurrence, particularly in inland and northern sites; however, it may be native (archaeophyte) at some sites in coastal southern England, particularly in south-west England and the Channel Islands, where it occurs in open, seasonally wet, sandy or silty habitats that may represent its natural native habitat range in a Atlantic-fringe European context. The UK status is therefore often recorded as 'native or introduced depending on site' or as an archaeophyte (an ancient introduction, present before 1500 CE) at some sites in the south-west. In practical terms for a UK naturalist or gardener: Polypogon monspeliensis is a regular, naturalised, and locally frequent component of the flora of damp, open, disturbed, often coastal or brackish habitats in southern and western England and Wales; it is a scarce casual or rare naturalised species further north and inland; it is generally regarded as a non-native or uncertain-native species in the UK and is not a UK Biodiversity Action Plan priority species.

Polypogon monspeliensis (annual beard grass, rabbit-foot grass) is an annual grass of wet, open, often coastal or brackish habitats in the UK, sometimes grown ornamentally for its very soft, silky, beard-like flower panicles produced from June to August. Leaves curl and yellow from drought and drying of the root zone, cold waterlogging on heavy soils, or the natural summer ripening and die-back of the annual lifecycle.

Drought and drying root zone

A plant of wet, seasonally flooded habitats, polypogon has a shallow annual root system that is not drought-tolerant. In a dry spell on light or freely draining soil, or in a container, the soft leaves roll inward and yellow at the tips rapidly; hot, dry UK summers cause the silky panicles to lose their fresh green colour and become dry and straw-yellow before their ornamental peak. Keeping the root zone consistently moist is the most important cultivation requirement.

What to do

Grow in moist to moderately moist, open, well-drained soil; a moist sandy or silty border position or the open edge of a garden pond suits it best. Water consistently through July and August when the flower heads are developing; drought curl significantly detracts from the ornamental quality of the panicles, which are softest and silkiest when the plant is well watered. Mulch lightly around the base to retain moisture without causing waterlogging.

Cold waterlogging on heavy soils

Although polypogon tolerates seasonal flooding in its natural habitat, prolonged cold waterlogging in poorly aerated, compacted clay soils causes root oxygen deficiency and leaf yellowing and curling. The distinction matters: polypogon thrives in moist, open, well-aerated wet sandy or silty soil, not in cold, heavy, compacted clay with no oxygen exchange.

What to do

Plant in an open-textured, moist, well-draining soil; avoid heavy, compacted clay that pools water without air exchange. Improve clay with grit and organic matter before planting. As an annual, polypogon can easily be resown in a better-suited position if the original site proves too heavy and waterlogged in a cold, wet spring.

Late-season ripening and die-back

Polypogon monspeliensis is an annual; as it ripens in summer to early autumn, the lower leaves yellow and curl in normal annual senescence, the soft green panicles turn pale straw-beige, and the whole plant dries as the life cycle completes. This is not treatable and is the natural end of the annual season. The plant self-seeds freely in open, damp, disturbed ground.

What to do

For ornamental use, harvest the silky panicles for drying while they are still at the soft, fresh-green stage; they dry beautifully and retain much of their silky softness at this early harvest stage. If left on the plant, the awns and seeds shatter as ripening advances, reducing ornamental value. Allow some panicles to fully ripen and shed seed in open ground for self-sown plants the following year.

Frequently asked questions

Why are my polypogon leaves curling?

Polypogon leaves curl most commonly because of drought and drying root zone (shallow annual roots; not drought-tolerant; soft leaves roll rapidly in dry spells; panicles lose their silky green quality early in drought; grow in moist, open, sandy or silty soil; water consistently in July and August; mulch to retain moisture), cold waterlogging on heavy soils (tolerates seasonal flooding in open, aerated wet soils but not cold, compacted, poorly aerated clay waterlogging; improve heavy clay with grit before planting; resow in a better-suited position if soil is too heavy), or late-season ripening and natural die-back (annual; lower leaves yellow and plant dries as it ripens in summer; harvest panicles at the soft green stage for drying; allow some seed to shed in open ground for self-sown plants next year). Moist, open, sunny position is ideal.

How do I grow polypogon monspeliensis ornamentally in the UK?

Sow directly in prepared, moist seedbed in April to May; surface sow fine seeds; thin to 10 to 15 cm. Or sow in modules under glass in March; plant out after last frost. Moist to moderately moist, open, sunny to lightly shaded position; moist sandy or silty soil; pond edge or moist raised bed. Water consistently through the growing season; drought reduces ornamental quality of panicles. Harvest for drying at the soft, fresh green stage before awns shatter. Self-seeds freely in open, damp, disturbed ground; naturalises without annual resowing in suitable conditions.

What is the difference between polypogon and phleum?

Both produce dense, spike-like flower heads but differ clearly on close inspection. Polypogon: very prominent long, spreading, fine awns on lemma and glume giving a distinctly bearded, silky-hairy, soft appearance and feel; heads more loosely cylindrical; annual; wet, open, disturbed, often coastal habitats; scarcer, mainly southern UK. Phleum (timothy, cat's-tail): short awns or no obvious awn; heads very dense, tightly cylindrical, firm to the touch; perennial; ubiquitous in UK grasslands, meadows, and pastures; extremely common throughout the UK. Touch is the quickest distinguishing test: polypogon heads feel silky-soft; phleum heads feel firm and dense.

Is polypogon monspeliensis native to the UK?

Complicated native versus introduced status. Native to the Mediterranean, Middle East, and south-west Asia; introduced and naturalised in many parts of the world. In the UK, probably introduced or archaeophyte (ancient introduction) at most sites; possibly native at some coastal sites in south-west England and the Channel Islands where it grows in open, seasonally wet, sandy habitats that may represent its natural Atlantic-fringe habitat. Generally recorded as non-native or uncertain-native across most of the UK. Locally frequent in damp, open, disturbed, often coastal or brackish habitats in southern and western England and Wales; scarce and casual further north and inland.