Imperata cylindrica 'RED BARON' Cogongrass, Japanese blood grass, kunai grass

Imperata is a relatively small genus that includes only 11 recognized and named species (as of 2022). It is a paradox that regardless of the low number of species it has so many common names, in English there are at least 13 of them. Its home is S.E. Asia, Micronesia, Australia, Africa and southern Europe, and it was inadvertently introduced to the southeastern USA at the beginning of the 20th century in the form of packaging material when importing goods from the countries of origin. Unfortunately, not too long after that, it was introduced intentionally as a plant designed to suppress erosion and to occupy neglected areas with poor soil. Apparently at the time, no one was properly informed of its invasive capability so within a few decades it escaped to both Latin and North America as well as the Caribbean, and became one of the ten most aggressive invasive plants, which, being fire-resistant, quicky spreads in disturbed areas and push out former vegetation. In many US states it is already banned from selling and cultivating under law.

Fortunately, the red-leaved form of imperata does not get invasive and rightfully belongs among the most beautiful types of ornamental grasses. It is called imperata cylindrica, was first described by Carl Linnaeus in 1759, and apart from the species there is practically only one variety Red Baron. You may still come across another name Rubra, however, modern science has proven that it is the same variety, only with an older name.

It gained its popularity not only due to its lush color, but also its low growth and soft leaves. They are 40-60 cm high, about 2 cm wide, bright green with rich garnet red and burgundy tones towards the tips almost throughout the growing season. They are deciduous, form strictly upright clumps and do not flower (or set seeds). However, if you see a flower inside the bunch, it is clear that it grows from a stem with solely green leaves which exhibits a reversion to the original species that would show tendency to spread rapidly. Remove it mercilessly as soon as you spot it.

Red imperata is such a pretty grass that it looks good on its own – it doesn't require companion planting and makes a good show in small spaces. Nevertheless, you can use it in mixed beds, too, ideally with smaller types of ornamental grasses (carex, stipa, ophiopogon) or groundcovering perennials with contrasting leaves (gypsophila, saxifraga, sagina or similar moss-type plants, etc.).

Imperata is easy to grow. It will be happy in almost any well-drained soil. It tolerates poor soil without nutrients and summer drought. It will grow in full sun as well as partial shade where it performs well as to good leaf colour. Red Baron grows slowly, and for mass plantings and dense nests use more plants. In the spring, cut back the entire plant just above the ground level. Hardy to approx. -29 °C. (USDA zone 5).

Last update: 06-09-2024