Ammophila arenaria

Ammophila arenaria, also known as marram grass or sea reed, is a low-maintenance perennial grass with greenish-grey, evergreen ornamental foliage. It grows in stiff and sharp clumps, producing flowers in compact spikes, golden then beige, contrasting with the bluish reflections. Its rhizomatous stump is particularly useful for dune and sandy soil stabilization. Perfectly hardy, it is a water-efficient plant that naturally grows in saline and sandy soils. However, it also adapts well to all dry and sunny soils in a natural-style garden.

Ammophila arenaria, commonly known as marram grass or sand reed, is a perennial herbaceous plant in the large family of grasses. Native to Europe, North Africa, and the Middle East, it has been introduced to the Americas, Australia, and New Zealand where it can even become invasive on often very arid, sandy and saline soils. Its system is extremely powerful, allowing the grass to spread as a carpet that fixes the sand, quickly colonising dune environments. 

Reaching 1.20 m (4ft) in height when flowering, it forms large clumps of foliage, about 70 cm (28in) in all directions. Its stump is vigorous, stoloniferous, and creeping. Its stems are stiff, upright, and arching, robust. Its persistent leaves are cylindrical like those of rushes, about 1 to 3 mm (1in) wide, smooth and greenish-grey in colour, becoming beige-ochre in winter and equipped with a nearly prickly tip. They are covered with a white to silvery blooms responsible for their bluish hue. The inflorescences appear from May to July, at the end of the floral stems, and remain on the plant until December. They are long spikes, 15 to 30 centimetres (6 to 12 inches) long, robust and compact, resembling those of wheat.

Marram grass is an ideal plant for coastal areas, especially for stabilising sand dunes. Stony and dry soils, as well as slightly arid slopes, are also favoured terrains for this grass that can withstand anything. It is also a very ornamental plant in borders or as edging, as well as for dressing up the terrace or patio in large flower pots. Due to its propensity to colonize the soil, it is preferable to plant it in a large buried container or to use anti-rhizome barriers if you want to use it sparingly in large borders. It can also be pruned short to create a sort of groundcover similar to a lawn. In a border, associate marram grass with low-maintenance asters, double-flowered fulva daylilies, rudbeckias, or large sedums.

This species is frequently attacked by the fungus Ustilago Hypodytes, also known as stem smut. No spike forms, instead large black mushrooms appear.