Phleum alpinum

The clearest mark of Phleum alpinum is its growth habit: it forms loose clumps of upright stems rather than spreading mats. The clumps stand 20 to 60 centimetres (7.9 to 23.6 in) tall.

The flowering head, called an inflorescence, is a dense, cylindrical to oval mass of spikelets. It can reach up to 6 centimetres (2.4 in) long and 1.2 centimetres (0.47 in) wide.

The spikelets are packed closely along the stem, which gives the head a compact, bottle-brush outline. Its overall shape is what sets it apart from more open grasses.

Few other grasses in its range combine such a dense, cylindrical head with a clumped, tufted form, so the head shape is the best field clue.

Phleum alpinum has a circumboreal distribution. It is found across northern areas of the Northern Hemisphere, including Alaska, much of Canada, Scandinavia, Central Asia, the Himalaya, Japan and Korea.

In the Americas, its range runs south through the mountains of the western United States and Mexico to Guatemala. It also extends down the Andes to southern South America.

The grass reaches far into the southern oceans. It occurs on islands in the subantarctic region, and on South Georgia Island it is one of the most common plant species.

Its habitats are cool and temperate to subarctic. Sightings cluster strongly in the summer months, with the peak in July and high counts in June and August.

Phleum alpinum is a graminoid, meaning a grass-like plant with narrow leaves and a tufted habit. It lives for more than two years and returns from the same root system each year.

Growth is slow. The plant builds up its clumps gradually, which helps it persist in cold, exposed sites.

Mature plants typically stand about 0.4 metres (16 in) tall, within a range of 20 to 60 centimetres.

Grasshoppers are the most important group of animals that feed on Phleum alpinum. Several meadow species, including Chorthippus parallelus, Chorthippus biguttulus and Decticus albifrons, are established partners, and other grasshoppers in the same group also feed on it.

True bugs (Hemiptera), moths and butterflies (Lepidoptera), and flies (Diptera) are also main groups of partners. Perching songbirds (Passeriformes) feed on it as well, making birds part of its food web.

Pigeons (Columbiformes) and gamebirds (Galliformes) also feed on it, but less often than the groups above.

Phleum alpinum suits cool gardens and tolerates severe winter cold, with a recorded minimum tolerance of -41.7 degrees Celsius.

It prefers medium shade rather than full sun, so a site with partial light suits it. Soil pH can range from about 5 to 7.5.

The plant has low drought tolerance, so it needs reliably moist soil. Its growth is slow, so it is best planted as a patient, long-term addition. Its bloom period falls in late spring, when its yellow flowers appear.

The plant has no known toxicity, so it is safe to grow where pets and children are present.