Ornamental grasses have much to offer gardens and are widely used in landscape and show gardens, but home gardeners have been slow to embrace grasses. This may be because many gardeners know little about ornamental grasses and often equate them with weeds.
Rest assured, there are lots of good ornamental grasses that are well worth a place in your garden. Varieties available for sale have little risk of becoming weedy as most are either sterile or do not produce viable seed – that is any seed is unlikely to spread and grow.
They can be used as a garden feature, as garden edging, for mass planting, as a lawn alternative, or enjoyed as part of a gravel or low water garden. Many can also be grown in a container. Good container varieties include Carex ‘Everest’ and ‘Evergold’.
They offer seasonal change from their fresh green or coloured new growth in spring through to dry foliage and seed heads later in the year. Clumps of grasses add volume to gardens and suit a wide range of garden styles from modern to cottage.
Grasses also offer an extra dimension to gardens as they sway or ripple in the wind. They can also be highly decorative in winter when glinting with frost.
Some grasses also have coloured or variegated leaves. Purple fountain grass (Pennisetum ‘Advena Rubrum’) is one striking ornamental grass with dark burgundy leaves and contrasting plumes of creamy flowers. Although it flowers, this variety does not produce viable seed.
Meet the grasses
Ornamental grasses are strappy-leafed plants that grow in clumps. There are two broad groups: true grasses and lilies that have a strappy or grass-like appearance.
True grasses are monocotyledons (often just called monocots), which not true flowering plants. Popular ornamental grasses include carex, Japanese blood grass, pennisetum and poa (which includes some native species and varieties including ‘Kingsdale’). The true grasses form clumps and have attractive fine or narrow leaves and seed heads that are often highly ornamental and persist for many months. Most grasses dieback over winter but come to life again in spring and ‘flower’ in summer and autumn.
To care for true grasses cut back old growth in winter to make way for new shoots that appear in late winter or early spring. Where new growth is already appearing among dry leaves, old stems can be groomed (pulled out) to make way for new growth. Wear gloves as some grasses are tough and may have serrated or sharp leaves. Large clumps can be divided if necessary. While ornamental grasses need little extra water or fertiliser, they can be fed in spring with an all-purpose fertiliser. Most grow best in full sun.
This group is made up of grass-like flowering plants often referred to as strappy-leafed plants. Most are lilies and some are very well-known garden plants including mondo grass and liriope, as well as the native plants lomandra and dianella.
Popular varieties of lomandra include ‘Seascape’ (pictured) and ‘Tanika’, while popular dianellas include ‘Little Jess’, ‘Little Rev ’ and ‘Cassa Blue’. Many are evergreen and can be used as low informal garden edging. They can be grown in full sun through to shade and have flowers that are often followed by ornamental berries.
While evergreen ‘grassy’ plants such as mondo grass and liriope need little regular care, lomandra and dianella may need grooming from time to time and can also be cut back hard to rejuvenate the clump. Fertilise in spring with native plant food.
Pictured: Lomandra Seascape.