Melica altissima is a perennial ornamental grass native to Siberia and northern Asia that flowers in the UK from May to July. It suits full sun or partial shade on well-drained loamy or sandy soils and tolerates a range of pH from slightly acidic to slightly alkaline. Rated H5, it is considered hardy for most UK gardens. Use it in borders or naturalistic plantings where summer flowering stems will add movement.

Tall melic (Melica altissima) is an ornamental grass that flowers May to July and prefers full sun or partial shade on well-drained loamy or sandy soils.

https://en.wikipedia.org/wiki/Melica_altissima

Melica is a genus of perennial grasses known generally as melic or melic grass. They are found in most temperate regions of the world.

Melica altissima

Tall melic | Melica altissima

Melica uniflora 'Alba' is a named cultivar of Melica in the grass family Poaceae. It produces flowering panicles in the UK from May to July. The plant grows as a grass-forming clump carrying erect flowering stems, and is selected under the 'Alba' name for a distinct trait within the species.

Melica uniflora 'Alba' is a named Melica grass in the Poaceae family that flowers in the UK from May to July.