Smaller cat's-tail: complete guide

Overview

Phleum bertolonii, commonly known as smaller cat's-tail or diploid timothy, is a perennial grass belonging to the Poaceae family. It is closely related to the familiar timothy grass (Phleum pratense) but is distinctly smaller in stature and occupies a different ecological niche. The botanical name honours the Italian botanist Antonio Bertoloni (1775-1869), who made foundational contributions to the knowledge of Italian flora.

The distribution of Phleum bertolonii is broad: the species is native throughout virtually all of Europe - including the Netherlands, Belgium, Great Britain and Ireland - extending through the Mediterranean basin to Iran. From Iceland and the Azores in the west to the Caucasus and Iran in the east, this is a genuinely pan-European grass. In Great Britain it is one of the most familiar grasses of permanent, nutrient-poor pastures and traditional hay meadows, where it contributes to the rich botanical mosaic of lowland and upland grassland.

For gardeners aiming to support biodiversity and native flora, Phleum bertolonii is worth knowing. On gardenworld.app you can explore how native grasses and wildflowers work together in front garden and meadow designs, giving both structure and ecological value.

The species also has agricultural significance: it is used in the UK as a constituent of grass seed mixtures for pastures on lighter, poorer soils where the taller Phleum pratense performs less well. In traditional hay meadow management, it is a characteristic and valued component.

Appearance and bloom cycle

Phleum bertolonii is a perennial, tuft-forming grass typically reaching 20-60 cm in height - noticeably shorter than common timothy, which can exceed 100 cm. At the base of the stems, the species forms characteristic bulbous swellings - a key identification feature that distinguishes it from Phleum pratense and that gives it the German name of 'knotiges Lieschgras' (knotty meadow grass).

The leaves are flat, ribbon-like and a fresh, matt green. They are rough to the touch along the margins and upper surface, which is typical of the Poaceae. The flower spike is cylindrical and tightly compressed, giving it a distinctive, club-like appearance. It is 3-6 cm long and considerably shorter and narrower than the spike of common timothy.

Flowering occurs in June and July. The spikes are initially greenish, gradually taking on a beige-purple tint as the anthers emerge, before becoming straw-yellow at full maturity. Wind pollination is the norm: large quantities of pollen are released during windy periods, which can cause problems for hay fever sufferers. After pollination, seeds ripen quickly and are dispersed partly by wind, partly by attachment of loose spike fragments to clothing and animal fur.

Ideal location

Phleum bertolonii is a plant of open, sunny situations. In its natural habitat it grows on:

• Permanent, nutrient-poor grasslands and pastures
• Dry to moderately moist calcareous or neutral grasslands
• Road verges and embankments
• Rocky cliff edges and stony, open ground near the coast
• Mountain pastures to considerable altitude

In a garden setting, Phleum bertolonii can be used in a wildflower meadow or native plant garden. Full sun is ideal; light shade is tolerated but results in laxer, less compact plants. A dry to moderately moist position is preferred; the species handles brief dry spells better than persistent waterlogging.

The plant is also suited to extensive green roofs and low-maintenance wildflower lawns, provided the substrate is free-draining. On heavier, clay-rich soils it will not perform as well as on lighter, more mineral-rich ground.

Soil

The soil requirements of Phleum bertolonii are modest, in keeping with its origin in nutrient-poor grasslands. It performs best on:

• Light, free-draining sandy or loamy soils
• Calcareous, mineral-rich substrates
• Low-nitrogen, low-phosphate soils

Rich, fertilised soils are counterproductive: high nitrogen levels favour more aggressive grasses such as ryegrass, which will quickly outcompete Phleum bertolonii. On nutrient-poor ground the species can hold its own and contribute to the botanical richness of a wildflower sward. A neutral to slightly alkaline pH of 6.5-7.5 is ideal, though the plant tolerates mildly acidic conditions too.

When establishing a native wildflower meadow, removing or stripping the upper, nutrient-rich topsoil layer before sowing is advisable. Phleum bertolonii can then establish successfully alongside other native grasses and flowering plants on the exposed, poorer subsoil.

Watering

Phleum bertolonii is not a drought specialist but tolerates short dry periods reasonably well, aided by the bulbous swelling at the stem base that provides some water storage. In a typical North-Western European summer, supplementary irrigation in open ground is not needed: rainfall covers the plant's requirements.

During unusually dry summers, on very sandy soils or during extended heat waves, a deep watering once a fortnight helps maintain vigour without creating irrigation dependency. In an established wildflower sward, avoid irrigation unless plants show visible drought stress: too much water favours vigorous competitors and disrupts the ecological balance of the meadow community.

In pots or containers, check weekly whether the growing medium feels moist at 2 cm depth, and water when it is almost dry - but never allow the medium to become waterlogged.

Pruning

Phleum bertolonii requires virtually no pruning in the conventional sense. As part of a wildflower meadow or traditional sward, it is managed through regular cutting as part of the overall hay-meadow or lawn management regime. The standard cutting programme for a wildflower meadow is:

• May - early June: If desired, an early cut before or just after early-flowering species have set seed, but only once the first native flowering plants have bloomed and distributed their seeds.
• July - August: The main cut after peak flowering. Wait until the seeds of Phleum bertolonii have ripened (early to mid August) before cutting.
• September - October: Optionally a second cut at low height to remove nutrients before winter.

Always remove and compost the cut material; leaving it in place returns nutrients to the soil and favours vigorous competitors. As a stand-alone specimen in a border or pot, Phleum bertolonii can be cut back to just above ground level in early spring to allow fresh new shoots to emerge.

Maintenance calendar

• January - February: No active care needed. Leave old stems for winter structure and overwintering insects if desired.
• March - April: In borders: remove dead stems from the previous year. Sowing fresh seed is possible from April once soil temperatures reach 8 degrees Celsius.
• May - June: Period of active growth leading to flowering. Do not cut a wildflower meadow until early-flowering plants have set seed.
• June - July: Flowering period. The cylindrical spikes are visible. Observe the characteristic plant structure and associated insect activity.
• August: Seeds ripen. Wait for most seeds to drop before cutting. Collect seed for sowing elsewhere.
• September - October: Second cut of the meadow sward if required. Always remove cuttings.
• November - December: Plant is fully cold-resistant; no special measures required.

Winter hardiness

Phleum bertolonii is a persistent perennial grass that survives winters across its entire range - from Iceland to Iran - without difficulty. The species is reliably cold-resistant down to minimum temperatures of -20 degrees Celsius and below (USDA zone 5 and colder).

In the Netherlands and Belgium, with their temperate maritime climate, Phleum bertolonii overwinters without any protection, including on extensive green roofs and wildflower lawns. The bulbous stem base swellings protect the vital growing points from freezing. Snow cover provides additional insulation but is not required.

Frost and snow damage to this species is virtually unknown in normal European winters. The only practical risk is mechanical damage from treading on frozen ground, which can injure the roots of perennial grasses. Avoid walking on a frozen wildflower sward or meadow.

Companion plants

Phleum bertolonii is best suited to plant communities that reflect its ecological niche: nutrient-poor, wildflower-rich meadows and swards of North-Western Europe. Good companions include:

• Festuca rubra (red fescue): another native grass that shares the same preference for nutrient-poor, free-draining conditions.
• Agrostis capillaris (common bent): finely branched, native grass for wildflower meadow mixtures.
• Leucanthemum vulgare (oxeye daisy): a radiant white-flowered native that thrives in nutrient-poor meadow conditions.
• Centaurea nigra (common knapweed): purple-flowered meadow plant that attracts a wide range of insects.
• Rhinanthus minor (yellow rattle): a hemiparasite that weakens vigorous grasses, making space for less competitive species.
• Plantago lanceolata (ribwort plantain): a low rosette plant that does well in short, extensively managed swards.
• Lotus corniculatus (bird's-foot trefoil): yellow-flowered legume, nitrogen-fixer and key food plant for common blue butterflies.

For design inspiration on wildflower lawns and native plant borders, gardenworld.app offers photo-realistic visualisations of your own garden before you plant.

Closing

Phleum bertolonii is a modest but ecologically valuable grass that shows its best qualities in the right context: a nutrient-poor, sunny site where it can join a rich community of native grasses and flowering plants. For gardeners wanting to support biodiversity and reduce maintenance intensity, smaller cat's-tail is a worthwhile addition to a wildflower meadow or native planting scheme. Specialist seed suppliers such as Emorsgate Seeds or Pictorial Meadows offer appropriate seed mixtures including this species. Choose this unassuming grass and you contribute to the conservation of a piece of North-Western Europe's botanical heritage.