My ornamental grasses are starting to flower at the moment, with their unusual silky feathers and fluffy plumes adding an interesting note to the late summer garden scene. The trend for using ornamental grasses came into vogue about 30 years ago, as part of a move to 'naturalistic' gardening, combining them with herbaceous plants that were adapted to similar conditions, such as the many prairie flowers from North America. Older gardeners who could remember the 'great pampas grass debacle' of the 1960s - when pampas grass self-seeded throughout gardens and beyond - were a bit wary of this grass fad, but fortunately most of those available these days do not have these scary tendencies.
Ornamental grasses bring a unique dimension to the garden with their graceful movement as they ripple and sway in the breeze, and their simple elegance, unique linear texture and arching form. They can be used as a focal point in a border, or repeated amongst plantings to create a unifying effect through the garden. The foliage provides an excellent contrast to big bold leaves or rounded shrubs. The interesting and often unusually coloured plumes of flowers add subtle hues to planting schemes from late summer into winter. There are some lovely coloured and variegated forms of ornamental grasses, and some will take on autumn tonings in their leaves as the colder weather sets in.
Most of these grasses are trouble free and easy to grow, and are adaptable to various garden positions. It is important to give them enough space, so that they are not hemmed in by other plants, causing them to lose the impact of their form. Some grasses don't like our humid summers, but cultivars of Chinese silver grass (Miscanthus sinensis) do very well in Sydney gardens and seem to create few self-seeding problems. They are probably among the most suitable and elegant grasses to use in our gardens. In general, they will grow in full sun and accept most soils, whether damp or dry, and the clumps become better as each year passes, making an impressive statement in the garden.
The cultivar 'Sarabande' has a fountain of silver-ribbed leaves (ht 1.6 m) and mauve-silver flowers held high above the foliage; its foliage takes on tawny hues through autumn and winter. Plants with flowers held on arching spikes or spires, such as Salvia or the big annual Amaranthus caudatus, can provide a satisfying harmony of form with this grass. 'Variegatus' (ht 1.5-1.8 m) has wider arching leaves, which are edged with creamy-white stripes; it has a pinkish-tan flower. It can provide an effective contrast to purple leaves, such as those of dark Canna or shrubby Euphorbia cotinifolia, as well as being a good partner to echo crisp white flowers, such as Shasta daisies. The cultivar 'Cabaret' (ht 1.8 m, pictured at left) is like a giant version of 'Variegatus', and forms a robust clump.
The cultivar 'Zebrinus' (ht 1.5-1.8 m) - sometimes known as zebra grass - has broad dark green leaves marked with horizontal yellow stripes, and pinkish-fawn flowers in late summer/autumn. With its interesting variegated leaves, it looks particularly effective with some of the yellow flowers of late summer/early autumn such as Dahlia, Rudbeckia and Salvia madrensis.
I do find I sometimes need to support these grasses with cradle stakes to stop them flopping over too much. Other cultivars, such as 'Hiawatha', have a more vertical growth habit. Miscanthus do tend to grow into quite big clumps eventually, so for smaller spaces, choose grasses that are more compact. One which has become popular in recent years is the lovely purple fountain grass, Pennisetum setaceum 'Rubrum' (ht 1-1.5 m). It has deep burgundy leaves that grow into an attractive shape, and fluffy purple-pink flowers throughout summer and autumn. The foliage is a dramatic contrast to silver leaves, such as those of Artemisia cultivars, or white flowers, and also can resonate with near-black blooms, such as Hemerocallis 'Black Ambrosia'. It looks wonderful grown in a large container.
On a smaller scale again, there is an excellent cultivar of the native grass Poa labillardieri, called 'Suggan Buggan' (ht 80 cm), which has lovely slim blue-grey leaves and dainty panicles of flowers in the same hue. It looks effective teamed with a broad silvery leafed plant such as Plectranthus argentatus, or white or very dark blooms. Native grasses offer a number of interesting possibilities for garden uses, which I am keen to explore, and I would love to know which ones people have had success with in Sydney.
I cut all my ornamental grasses as low to the ground as possible around June so that the regrowth can commence in late winter. Propagation is by division. They only seem to need routine feeding and watering once established, and seem to suffer from no pests or diseases. What more could we ask of a plant?
Blog originally posted on 28 February 2010; updated 14 February 2021.
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