Gentle and not so Gentle Giants
B. Rosie Lerner, Extension Consumer Horticulturist, Purdue University
Tall ornamental grasses can add drama to the home landscape either as a screen for privacy or focal specimen amongst other plants.
Arundo donax (giant reed) is no doubt the most dramatic as it towers up to about 14 feet in our climate (Figures 1 and 2). While it has a bad rap for being invasive in some warmer climate states, in Indiana it slowly spreads to form small colonies via large rhizomes (underground stems.) Although capable of setting seed, in short-growth season areas, it may not flower or it may not produce fertilize seed.
Saccharum ravennae (formerly Erianthus ravennae) (Ravenna or Plume Grass) is another stately grass, reaching about 6 - 12 feet when in bloom (Figure 3). Sometimes called hardy pampas, it is not a true pampas and not quite as tall. Ravenna grass has a clump habit so does not form colonies like the giant reed, but it is capable of self-seeding.
Neither of these towering beauties is native to the US, so if you prefer to stick with native species, you might consider some of the following, though none are as tall as the above mentioned species.
Andropogon gerardii (Big Bluestem) reaches 4-6 feet tall with a bunch habit, will self-seed and naturalize (Figure 4).
Spartina pectinata (Prairie Cordgrass reaches 4-8 feet tall with a vigorous, spreading habit (Figure 5).
Panicum virgatum (Switchgrass) reaches 3-5 feet tall with primarily a bunch habit but will slowly spread over time (Figure 6).
Click image to enlarge
Figure 1. Giant reed (Arundo donax)
Figure 2. Giant reed (Arundo donax)
Figure 3. Ravenna/ Plume Grass (Saccharum ravennae)
Figure 4. Big Bluestem (Andropogon gerardii)
Figure 5. Prairie Cordgrass (Spartina pectinata)
Figure 6. Switchgrass (Panicum virgatum)