Sally Petitt takes a moment to appreciate the sensory experience of grasses in both garden and landscape
Images Howard Rice
Grasses can be invaluable in adding texture, sound and movement to a garden or wider landscape. The swaying stems of a field of barley (Hordeum vulgare) are especially mesmerising when moving rhythmically en masse, while the rustling leaves of great reedmace (Typha latifolia) bring a distinct sound to the fenlands.
While most of us will not be able to consider including them on such a large scale in our own plots, ornamental grasses can transform a planting scheme in even the smallest of spaces. Not only do they bring elemental interest, they are also beneficial to our wellbeing: their subtle colouring in the growing season and neutral tones through autumn and winter are calming; their graceful movement as they rhythmically sway is enchanting; and their sound in a breeze is soothing.
Who can resist walking beside a swathe of North African feathertop grass (Cenchrus longisetus) and brushing their hands through the soft foliage and flower spikes? I know I can’t!
We are family
A range of grasses are favoured by gardeners, but did you know that the grass family (Poaceae) is one of the largest plant families, containing approximately 800 genera and 12,000 species? It’s a truly cosmopolitan family too, occurring from sea level all the way up to high altitudes, in temperate, tropical, arid, wetland and mountainous habitats, and plants can be terrestrial or aquatic.
Records indicate that grasses are the main component in 25% of the Earth’s vegetation cover and form the basis for essential ecosystems such as savannahs and prairies. Poaceae is also the most economically important plant family, containing crop plants such as wheat, barley, oats, maize, rice, rye, sorghum and millets, and also bamboo which is used in construction.
Today, grasses are used in the production of many items such as fibres, starch, aromatic oils, alcohol, sugar, baskets and buildings. Some members of the family are also invaluable in stabilising soils such as the native marram grass (Ammophila arenaria), which grows on coastal sand dunes. Some have also been widely used in traditional medicines for the treatment of ailments. And, of course, many provide food and habitat for a large range of birds, mammals and insects.
Members of the grass family are distinguished by their slender leaves bearing longitudinal parallel veins, and their panicles of spikelets, or grass flowers. Species are evergreen or deciduous, and are annual, biennial or perennial in their habit, with the bamboos being woody. Their stems, or culms, are hollow and the sheathed leaves have a broad base with which they appear to clasp the stems.
Grasses in the garden
Given the size of the family, and its wide ornamental appeal, there is a grass for all garden styles and conditions. A grass garden can be impressive, and here at Cambridge University Botanic Garden our Systematic Beds contain a display of members of the Poaceae, which highlights the diversity within the family.
Whatever your situation there will be a grass for you. If you’re feeling encouraged to dive into the world of grasses for the first time, be sure to pick the right plant for the right place. When selecting, consider your soil type and light levels to ensure you make the correct choice.
If you have light shade and moisture, Japanese forest grass (Hakonechloa macra ‘Aureola’) is a great choice. Anemanthele lessoniana (pheasant’s tail grass) is the only component in our grass maze, and this enjoys dry conditions in sun or shade, and its billowing mounds are attractive, tactile and full of movement throughout the year.
Grasses can add form and texture to herbaceous beds, breaking up the cacophony of colour and the rigid forms of many perennials with their graceful form and motion. Nassella tenuissima, or Mexican feather grass, grows to approximately 60cm tall, and along with greater quaking grass (Briza maxima) is perfect for inclusion in a sun-baked gravel garden. A taller species, giant oat grass (Celtica gigantea) has flower stems to 2.5m that take on a golden glow in sunlight, making for a wonderful specimen, while Calamagrostis x acutiflora ‘Karl Foerster’ is an erect perennial favourite, valued for adding punctuation to a border.
Poaceae is not only the most important family of economic value, but its diversity also offers a great selection of species for use in our gardens, each of which brings movement, texture and sound to these treasured oases. I for one can’t imagine a garden without them.
Gardening jobs for September
1. Continue harvesting fruit and vegetables such as potatoes, beetroot and tomatoes.
2. Divide and plant congested clumps of herbaceous perennials such as Geranium and Epimedium.
3. Plant spring flowering bulbs like Crocus, Narcissus and Fritillaria.
4. Collect and sow seed from perennials and annuals.
5. Install water butts beneath downpipes to store water for use later in the garden.
Sally Petitt is head of horticulture at Cambridge University Botanic Garden