Plant profile:
Deriving their name from the Latin words penna ( feather) and seta (bristle), these grasses are more often grown for their inflorescences than their foliage
pennisetum Head gardener Matthew Reese selects 13 of the best fountain grasses for late summer borders
Ifirst became aware of the attractions of Pennisetum during my student days at Kew. Adjacent to the School of Horticulture is the Grass Garden, a wonderful oasis with a central patch of lawn that became a bolthole for students looking to relax between lessons. From this spot you could observe how visitors, particularly children, were drawn to the fountain grasses when in f lower, stroking the long, bristly plumes as they would the tail of a cat.
The genus Pennisetum comprises about 80 species, mostly perennial, from sub-tropical and warm temperate regions of the world. Many are highly ornamental, and for the most part, clump-forming (a few are rhizomatous), with neat tussocks of arching foliage from which numerous fountains of plume-like inflorescences emerge from mid- to late summer. The seedheads persist throughout the winter and the sere foliage can be an asset during the colder months when brown becomes more valuable in the garden.
Although many pennisetums are winter-hardy, they require hot summers to perform well, and consequently have often been dismissed as too late to be useful, or thought suitable only for the warmer counties of southeast England. However, a recent influx of new selections proven to be hardy include plants that will thrive in northern counties. Pennisetum orientale ‘Flamingo’, P. orientale ‘Tall Tails’ and P. ‘Fairy Tails’ are good examples. The nursery industry has also seen a recent surge in demand for tender grasses for use as bedding, and P. x advena ‘Rubrum’, along with P. glaucum ‘Purple Majesty’, have become popular.
With so many pennisetums now on offer, we can fully recognise their terrific garden potential. When planting Pennisetum, consider how to bring out the best of the plant, either by planting in drifts, or, if your chosen species or cultivar is bold enough, leaving it to stand on its own. The lovely f lowers and foliage combine well with late-summer perennials, such as asters or Helianthus. Years ago at Sissinghurst Castle, I was particularly taken with the combination of P. villosum with Hylotelephium ‘Herbstfreude’ and Eucomis autumnalis. The pastel colours were harmonious, and the shape and texture of the soft, fluffy grass flowers contrasted well with the eucomis and succulent sedum.
The shorter species are particularly well suited for the front of the border. The foliage remains smart from head to toe and acts as a useful screen when placed in front of taller perennials, such as phlox, the lower leaves of which often become ragged as the season progresses. The fine foliage and soft, arching flowerheads sway in the slightest breeze and this attribute is highlighted when planted next to a stiff shrub. Nearby plants with larger foliage will also accentuate the fine features of pennisetums and make the composition more interesting. When I worked at Great Dixter, the combination of the magnificent P. x advena ‘Rubrum’ with its sienna-red foliage looked particularly dramatic in the Old Rose Garden in front of the wide, paddle-like leaves of the variegated Canna ‘Striata’.
Once the surfeit of lush greens of the warmer months has faded, we appreciate the brown shades of structural plants proudly standing through the winter much more. Many of the pennisetums are up for this challenge, and will certainly help your garden earn its keep for as much of the year as possible. It is well worth seeking out Knoll Gardens, Dove Cottage Nursery and Garden, or the Grass Garden at Kew for inspiration on using grasses in the garden.
Author Matthew Reese is head gardener at Malverleys in Hampshire. Matthew’s recommendations for pennisetums continue over the next five pages.