There are many species of the grass genus Pennisetum, including the agronomic crops pearl millet and elephant grass (used for forage and now for biofuel), plus numerous landscape ornamentals, including ‘Purple Majesty’ ornamental millet (P. glaucum). Fountain grass, P. alopecuroides, is a perennial ornamental grass, with various cultivars hardy from zone 4 or 5 through 10. This warm season grass native to meadows and open woods, alongside streams of Eastern Asia (mainly China and Japan) and Australia has finely textured foliage and elegant form. The leaves and flower spikes swaying in the breeze adds movement to the landscape.
The deep green foliage forms a dense but graceful clump 12-48″ tall, depending on the cultivar. Growth is upright at first, then the leaves arch at maturity, resembling a fountain. The length and width of the long, tapering, subtly serrated blades varies greatly among the cultivars. The leaves turn orange-bronze in autumn, eventually fading to a dull beige. The foliage remains fairly upright to provide some winter interest.
In late summer showy, white to pink, copper or purple flower spikes are produced above the leaves. The flowers are concentrated in the narrow bottle-brush form on the end of the spike and seeds are hidden within the bristles of the fuzzy-looking inflorescences. The flower spikes are particularly dramatic when backlit, so try to position the plants to take advantage of the sun behind them. The plants may not bloom when the growing season is very short. The inflorescences do not last the entire winter, only holding together for a few months as the seeds begin to shatter after a few hard freezes.
Fountain grass is easily grown in most soils and does best in full sun, although it does tolerate part shade (but will not flower well). Although it prefers fairly dry soils and is drought tolerant once established, it also grows in moist, but well-drained soils. Plant the grass with the crown of the plant above ground level to prevent crown rot, especially in moister situations. It may decline in very wet years or poorly drained soils. The tips of the leaves may turn brown if not watered in drought conditions. The species is marginally hardy in northern areas of zone 5 and large portions of the crown die in some winters. These grasses have few pest problems and are considered deer resistant.
As a warm season grass, it doesn’t start growing each year until the ground has warmed up. This gives the gardener time after the winter ends to trim the previous year’s growth before the new shoots appear. Trim the grass to 3-6″ above the ground. This is easily and neatly accomplished with hedge trimmers, especially if the clumps are tied up with string first. As individual clumps age the center of the plant often dies out, forming an open ring. Divide and replant after shearing to rejuvenate clumps that have an open center. Division is suggested every three years but not all clumps need it that frequently.
Use fountain grass as a specimen plant or focal point in smaller areas. In bigger gardens, use plants individually or in small groups with perennials and shrubs to provide a contrast of texture or massed in large groups as a tall ground cover. It is better suited for the residential landscape than many other ornamental grasses because of its moderate size. It works well in rock gardens, the front of borders, and around water gardens or on the banks of streams or ponds – it has a particularly beautiful effect when reflected in water. Some people feel it looks weedy early in the season before the inflorescences appear but others like its soft, fine texture and movement in the breeze at all stages of growth. It makes a good informal edging along hardscapes or to soften the edges of paths. Try planting it near lady’s mantle (Alchemilla mollis) or purple cultivars of Heuchera for dramatic contrast. It provides a good foil for variegated plants, such as low-growing Lamium maculatum ‘Anne Greenaway’ or ‘Pink Nancy’ or a taller shrub like ‘Carol Mackie’ Daphne.
Fountain grass can be grown from seed – and many types self-seed readily (to the point of being weedy), but do not always come true from seed. In colder climates this species never becomes invasive like it can in warmer areas. Sow seeds in early spring, barely covering the seed. Transplant into the permanent position in the garden in summer. Plants are also easily propagated by division in spring as growth begins.
- ‘Cassian’ has dusky brown flowers and rich golden fall color with orange-red tints. It is about the same size as the more common ‘Hameln’, although it’s leaves are coarser, with some red tinting under the right environmental conditions. It was named for German horticulturist Cassian Schmidt. It is rated as zone 5/6.
- ‘Fox Trot’ is listed as hardy to zone 4. It is much taller, with more rosy- or black-colored inflorescences.
- ‘Hameln’ is one of the hardiest cultivars, rated at zone 5, but often seen growing in zone 4 gardens. It is more compact than the species (18-24″ tall and wide), with bright green foliage and silvery-white flowers that bloom about 2 weeks earlier than the species. It does not reseed as prolifically as the species and many other cultivars. It is the most commonly available cultivar in the nursery trade.
- ‘Little Bunny’ is a super dwarf form only about a foot tall. It flowers lightly but more or less continuously from mid-summer (up to 2 months earlier than the species). The flowers are light green in the small inflorescences that resemble bunny tails. It is particularly useful in gardens with limited space.
- ‘Little Honey’ is a variegated sport of ‘Little Bunny’ with green leaves with a fine white margin. It is even smaller than ‘Little Bunny’ but is still quite vigorous, with miniature tan plumes 6-12″ tall. It needs a special site, such as in the rock garden, so that it won’t get lost in the landscape.
- ‘Moudry’ (often called black fountain grass, P. alopecuroides var. viridescens) has deep maroon flowers produced 3-5 weeks later in the season than the species. The plant is vigorous, growing to 2½ -3 feet tall and wide, with wider leaves and more upright inflorescences than the other types. It is a prolific seeder in warmer climates and is not as hardy as many of the other cultivars, often rated only zone 6. It was introduced by the National Arboretum from a batch of Japanese seeds.
- ‘National Arboretum’, an introduction of the U. S. National Arboretum, is similar to ‘Moudry’ with dark, almost black inflorescences late in the season, but has better flowering. Like ‘Moudry’ it has a tendency to self seed prolifically in warmer climates and is hardy to zone 6 (maybe the warmer parts of 5).
- ‘Redhead’, a selection from seedlings of ‘National Arboretum’, has big, smoky burgundy inflorescences and blooms earlier than the parent type. It is hardy to zone 5 or 6.
- ‘Weserbergland’ is another dwarf type, growing 2-3 feet tall.
– Susan Mahr, University of Wisconsin – Madison