Design a grass garden
A garden designed to exhibit some of the most striking and delightful of the grasses and their relatives might start with Saccharum ravennae, with its high, vertical line and autumn red-orange tones, or with one of the slightly shorter moor grasses (Molinia spp.), such as the aptly named M. ‘Windspiel' or M. ‘Skyracer'. These could be juxtaposed with Miscanthus ‘Giganteus' or M. sinensis ‘Grosse Fontane' for width and bulk-both cultivars have somewhat drooping blades that resemble a fountain or waterfall. M. s. ‘Strictus', with its horizontal variegation and rigid upright form, or the more arching M. s. ‘Zebrinus', would provide good contrast. The most highly recommended and utterly graceful Miscanthus cultivar is M. s. ‘Morning Light', though I am still fond of the older M. s. ‘Gracillimus'. All of these grasses look wonderful next to water, too. They'll tolerate moist soil but don't like wet feet.
These tall, solid grass forms can be set off by the softer, billowy form of the North American Panicum and hair grass (Deschampsia), fairy tale grasses that sparkle with dewdrops in the morning or after a summer rain. ‘Prairie Sky' switch grass (P. virgatum ‘Prairie Sky') is one of the bluest of that genus, and P. v. ‘Heavy Metal', a winner for colour and form, can create a diaphanous curtain between areas of the garden or soften the look of stronger, vertical forms when planted at their bases. A new Deschampsia, D. flexuosa ‘Tatra Gold', looks like golden hair with a midsummer haze of bronzy purple flowers and is superb as a foil for stronger forms or in a container.
Pick up the blue colour and anchor Panicum with Helictotrichon sempervirens ‘Saphirsprudel', the bluest of the spiky, fine-textured oat grasses; if your climate allows it, add a drift of the contrasting golden hakone grass (Hakonechloa macra ‘Aureola'), with perhaps the less commonly used but larger plain green form (Hakonechloa macra) as a lovely background. Hakonechloa spp., which like moist soil and a bit of shade, are most effective planted in groups. Low-growing plants such as Pennisetum should also be grouped (they look good in containers, too).
Grasses at the water's edge
Good choices for moist soil are Bowles golden sedge (Carex elata ‘Aurea'), C. conica ‘Snowline' and C. morrowii cultivars. ‘Aurea' is particularly effective when paired with a broader-leafed water plant. A new introduction, C. nigra ‘Variegata', has light green foliage edged in soft yellow and small, black flowers.
In the water, the white bulrush (Schoenoplectus lacustris ssp. tabernaemontani ‘Albescens') looks dramatic with its slender, metre-high, white-striped stems. The small, delicate, erect form of umbrella plant (Cyperus alternifolius ‘Gracilis') has flower heads 10 centimetres in diameter and makes a stunning, non-hardy annual backdrop for the tiny (10 to 15 centimetres) dwarf horsetail (Equisetum scirpoides) with its black horizontal banding. Or try corkscrew rush (Juncus effusus ‘Spiralis'), which looks like a mini Harry Lauder's walking stick or a bad hair day (the new cultivar ‘Lemon Twist' gives you bad hair with a bleached blond stripe).
Other plants that flourish in damp or wet conditions are the dense-clumping native soft rush (J. effusus), variegated Japanese rush (Acorus gramineus ‘Variegatus') and gold-toned Japanese rush (A. ‘Ogon'). A. g. ‘Minimus Aureus', a new introduction, is a miniature with golden foliage that makes a great groundcover around rocks.