Friday, June 1, 2007
Guilt By Association
A recent visitor commented that she could not believe I would choose Purple Fountain Grass (Pennisetum setaceum ‘Rubrum’) as an accent plant in my garden. She had read in the newspaper that fountain grass was one of the causes of the intense wildfires that have plagued Arizona in recent years. She said the grass was a noxious weed and had gone so far as to destroy the few she had in her garden and had convinced her neighbors to do the same. She was well intentioned, but I assured her that Purple Fountain Grass is NOT a noxious weed, and that regular Fountain Grass (Pennisetum setaceum) is the culprit that is causing problems. The key difference is Purple Fountain Grass does not reseed, and regular Fountain Grass does, vigorously!
Purple Fountain Grass is suited to our climate and looks lovely as it shimmers and sways in the breeze. The burgundy color adds drama and contrast to desert landscapes and looks especially nice when combined with the grays of Agave, Bush Morning Glory, and Dusty Miller. Considered a perennial in our USDA Zone 9, it looks better if sheared back to about 12 inches in late winter. We accomplish the shearing by tightly tying a string around the plant and then cutting it under the string to the proper height. The bundled remains can then be easily disposed of without extra work. After shearing, it begins to grow new foliage immediately, and will have new plumes within a month or so of shearing.
Regular Fountain Grass looks different from the ‘Rubrum’. The grass is pale green and the plumes white. Introduced years ago as a landscape plant, Fountain Grass became very popular, which lead to the problem we have with it now. The plant is highly aggressive, readily reseeds, and quickly overruns native plants. The seeds are widely disbursed by wind, water, animals, and even vehicles. The seeds can live for up to six years and then sprout, making it an ongoing threat. Areas overrun with Fountain Grass are susceptible to intense wild fires, which easily kill off native vegetation. Arizona homeowners are regularly urged to destroy Fountain Grass, being careful not to disburse even more seeds in the process.
My visitor had the right idea, just the wrong plant. I wonder what her neighbors would say if they knew!