Pennisetum setaceum 'Rubrum', purple fountain grass

Pennisetum setaceum ‘Rubrum’ is an annual or perennial ornamental grass.  It is named for the arching spikes of purplish flowers that grow out of its mass of long, slender burgundy-colored leaves.  The Latin word penna means “feather” and seta means “bristle”.

It belongs to the Poaceae family which is the fifth largest plant family with around 780 genera and 12,000 species.  The genus Pennisetum is widespread and native to Africa, Asia, Australia, Latin America and has been brought to and introduced in Europe, North America, and some Pacific islands.

This plant and its seeds are also considered browse by some herbivores such as the Chestnut-breasted Mannikin (Lonchura castoneothorax).  Mostly, however, it is prized as a container or border plant for residential and municipal areas (Gilman, 1999).

P. setaceum ‘Rubrum’ grows well in full sunlight, in many different soil types and is considered to be easily grown without much care.  Its USDA Hardiness Zone is 9-11 (Gilman, 1999).

The flowers are very large and turn from brownish red to tan as it ages throughout the year.  Its height ranges from 35–47 inches (90–120 cm) and its spread can be 23–35 inches (60–90 cm).

Due to its fast growth rate and high seed production, it has spread into the wildland-urban interface and is now considered to be invasive.  It is most problematic in dry, arid climates in the southern United States, Australia, Europe, and parts of Africa (Kaufman, 2012).

Overall, Pennisetum setaceum is a viable option for urban and residential landscaping.  However, because of its capacity for invasiveness, caution should be taken when deciding where and how to plant this grass. 

Gilman, Edward. 1999. Pennisetum setaceum ‘Rubrum’ Purple Fountain Grass. 10 October 2020. https://edis.ifas.ufl.edu/pdffiles/FP/FP46400.pdf

Kaufman, Sylvan. 2012. Pennisetum setaceum (fountain grass). 10 October 2020. https://www.cabi.org/isc/datasheet/116202#tosummaryOfInvasiveness