How to grow grasses
Many gardeners overlook grasses, but hundreds of different kinds are available, and they offer diversity of form, colour and foliage. Many bear attractive ornamental flower and seed heads that can be dried.
Grasses enliven plantings with their rustling movement and varying textures, adding extra depth and structure. You can achieve dramatic effects by planting ornamental grass as individual living sculptures or en-masse in large swathes. Equally, grasses can form an eye-catching display when inter-planted with foliage and flowers in beds or containers.
In summer, annual grasses hold special appeal, while in autumn and winter the foliage and seed heads of perennial grasses prolong the seasons with colour and interest. Providing about 20% of the earth’s vegetation cover, wild grasses can survive extremes of climate from the droughts of arid savannahs to the moisture of boggy prairies; this resilience makes them ideal garden plants.
Preparing and planting grasses
Many different planting schemes and styles will be enhanced by including ornamental grasses. Use large specimens such as forms of miscanthus and arundo as individual specimen plants or for seasonal screening. Select the right plant for the right place to avoid disappointment. Planting should take around 30 minutes.
- Establish your aims: bear in mind eventual height and spread and what you want to grow with it. Are you looking to provide a naturalistic-style planting effect or to use grasses as architectural accent points in a border?
- When to plant: spring is the ideal planting time; the soil has begun to warm, encouraging rapid rooting, and spring showers mean less watering is needed to get the grass well established before winter. It is not advisable to plant in autumn as grass roots are no longer active.
- Sun or shade: if choosing a grass for shady areas, enrich the soil by digging in well-rotted organic manure or compost before planting. Sun-loving grasses suit an arid area in full sun perhaps with added sand or gravel to improve drainage. Prior to planting, water all grasses well while still in the pot.
Types of grass
There are many different forms of grass, so select seeds depending on the style of garden you want, its size, the other plants you are growing and the type of soil you have.Large grasses
- Miscanthus sinensis: is a hardy giant grass, great for adding height and drama to a garden. It can be planted as a solitary specimen or in small groups. Most varieties have large dark green leaves with white stripes, on thick shoots. Up to 3m.
- Arundo donax (reed of the bible): will add an exotic look to the spring and summer garden. Its reed-like shoots have blue-grey leaves and its plume-like flower heads can be used in dried floral arrangements. Best planted as single specimens, it benefits from cutting down to the base in late autumn each year. Up to 6m.
- Stipa gigantea (golden oats): produce dense clumps of evergreen, blue-green leaves with tall flowering stems in autumn. The upright flower spikes are straw yellow with loose heads of oat-like flowers that wave in the breeze. It prefers a dry position, thrives on poor soil but needs protection in winter. Up to 2.5m.
- Luzula sylvatica (greater woodrush): is strong hardy grass, ideal for edging or mixing with shrubs. Tolerant of shade, it makes an effective ground cover especially useful for under trees. Its brown flower spikes are small and insignificant. Up to 40cm.
- Carex comans bronze-leaved (pictured with hellebore, right): has a gently arching habit, red-brown narrow leaves, and light brown flower spikes in summer. Preferring damp, humus-rich soil, it is useful for brightening a dull, shaded corner. Up to 50cm.
- Briza maxima (quaking grass): has dainty flower stems carrying heart-shaped spikelets that tremble in the wind. It has blue-green, narrow, upright leaves and green flowers maturing to yellow then white. It dies after setting seed in autumn, but seed is easily resown. Up to 50cm.
- Hordeum jubatum: has bright green leaves complemented by elegantly arching green/yellow bristles ripening to gold tinged with red. Young flower heads can be dried. Up to 60cm.
Many bamboos prefer a sheltered position, in sun or light shade and will be damaged by strong winds. When planting bamboo dig a hole twice the width of the root ball; this allows for backfilling with a mixture of well rotted manure, compost or bone meal.
- Fargesia murielae (Muriel bamboo): is one of the hardiest bamboos, with a compact, clump-forming habit, spreading by a dense creeping rootstock rather than runners. Elegant upright yellow/green shoots arch over at the tips and become more drooping as the weight of the foliage increases. The light green leaves are delicate. Up to 3m.
- Phyllostachys nigra: has unusually coloured shoots – bright green when they first emerge, then blotched with black before turning completely black in maturity. The foliage is dense, so remove dead or thin stems to aid aeration and reveal the shiny black stems. Up to 6m.
- Sasa veitchii: is large-leaved and dense, and ideal for ground cover or under planting. The thin stems can be cut easily for arrangements. The leaves are dark green with a white edging, which increases in winter. Sasa can become invasive, so install a rhizome barrier prior to planting if you do not want it to spread rapidly, or plant in a tub. Up to 80cm.
Taking care of grasses
- Watering: frequency depends on the genus and species you have, and the humidity present in the atmosphere. Some bamboos and grasses – those that require high nutrients – will benefit from regular feeding and a mulch of organic matter, such as compost.
- Winter protection: in winter let grass die back naturally, as the extra layers provide added protection from the elements. Cover frost-sensitive grasses with a layer of dry leaves secured with brushwood. Loosely tie large grasses such as pampas grass around the base of the clump.
- Propagation: seedlings of species that have self-seeded can be left in position or potted up and grown on. However, seedlings of cultivated varieties may not be the same as the parent plant and could be more vigorous, so these should be removed. Grasses can be divided in spring when new shoots are beginning to emerge. Take a sharp spade or fork and divide the clump into smaller pieces, ensuring plenty of rooting material is still attached to each new piece and then re-plant.
- Pests and diseases: most grasses remain pest and disease free. Occasionally in excessively wet weather the foliage may suffer from rust disease. Prevent by spacing plantings to provide free air movement and circulation, and water potted plants from below.
Grass planting combinations
Ornamental grasses work well when intermingled with other plants
- For bold foliage: mix with ricinus, hostas, ligularia, astelia, phormium, cordyline, heucheras, gingers, cannas, eucomis, fatsia and mahonia.
- For bright colours: combine with sunflowers, daylilies, echinacea, rudbeckias, crocosmia, helenium, dahlias.
- For late season interest: use plants with seedheads such as eryngium, sedum, poppy, verbascum, achillea. Warm hues of stipa and carex grasses can be complemented by deep pink and red nerines and schizostylis.
- Annual plants for mixing: antirrhinums, calendulas, cleome, salvias.
Grass provides about 20% of the earth’s vegetation cover.