Architectural Plants. Christine Shaw

site, where it has permanent access to water. It will die down every year and send up new shoots in spring. This plant can also be grown very successfully in a conservatory, where it will remain evergreen. Stand it in a large saucer of water and never let it dry out. It is also suitable for gardeners who kill through ‘kindness’, as it is impossible to overwater.

      Cyperus alternifolius can be propagated by seed or division, but there is another way that is much more fun to try, especially for children. Chop off one of the heads (from the plant, not the children!) with a long piece of stalk attached. Turn it upside down and push it into a bottle full of water. Roots will form from what was the top, and new shoots will start to form. Keep the water fresh and clean so that the whole process can be observed. When a manageable-sized plant has developed, remove it from the bottle and pot it up in fresh compost.

      This grass will grow in virtually any soil, and can be sited in full sun or light shade. Keep away from strong winds, otherwise the fragile stems will be blown flat. It is easy to maintain; watering is the only thing to worry about. Older leaves can turn brown and fall down. Cut these right back to their base with secateurs to keep a tidy appearance. Aphids can be a nuisance on new growth in spring and early summer.

      A word of warning: if this plant is being purchased with the intention of planting it near a pond or stream containing fish, check with the nursery as to what compost it has been grown in. Many nurseries mix a nasty chemical called Suscon Green into the soil. This is to kill vine weevils, which can be a real problem for plants grown in pots, but it will also harm other wildlife, so take care to wash the existing soil from the roots and repot the plant into something safer.

       Cyperus papyrus

       Papyrus

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      Cyperus papyrus associates brilliantly with all kinds of pools and ponds, both inside and out.

      An enormous plant, big enough at maturity to fill a spacious corner in even the most generously proportioned conservatory. Thick, fleshy stems are sent up from the rootstock to a height of 2.5m (8ft), quickly making a thick clump that gradually spreads out across the surface of the pot and beyond its perimeter.

      This plant is ideal for gardeners who tend to be heavy-handed with their watering – it is virtually impossible to overwater, and needs a constant supply. During its growing season from early spring to the end of summer, a large saucer or shallow trough placed underneath each pot and kept full of water will prove beneficial. Keep this water clean – if it starts going green or cloudy, change it immediately, as murky, stagnant water could lead to root problems. It will also start to smell unpleasant.

      Full bright light is essential, especially from above. If the light levels are too low indoors, the stems will not remain upright. Instead, they will collapse and become very untidy. If grown in the correct position, the stems will fall over only when they are old or damaged. These should then be chopped off at the base with a sharp knife. Regular repotting each spring will be required, until its size makes this impractical. The clumps can then be divided up instead to make smaller plants.

      Older plants send out new growth from around the perimeter of the pot, which grows horizontally as if it is trying to escape. These can be removed to keep the clump tidy as an alternative to constant repotting. These plants enjoy being potted into a loam-based soil such as John Innes no. 2, which should give good results. Feed annually in spring with a liquid nitrogen-based food. Aphids can be a bit of a problem during spring and summer.

      Although almost freezing temperatures can be tolerated, Cyperus papyrus is much happier if the temperature can be maintained at no lower than 6°C (43°F). Any less than this means that watering should be almost withdrawn, so that the compost dries out slightly until the weather warms up again.

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      Each stem produces a fine head of beautiful fluffy filaments, which form a spherical shape 30cm (1ft) across.

       Luzula sylvatica ‘Marginata’

       Woodrush

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      This grass is much more effective if planted in groups, rather than as single specimens.

      A low-growing grass, native to northern Europe, that is perfect for small gardens. Individual plants will spread out to only around 6ocm (2ft) and will take at least three years to do so. If a larger space can be provided, these plants look wonderful in large groups and used as groundcover. They are also very effective in groups underneath and around trees, where they appreciate the dappled shade provided by the tree canopy. If planted close together, they form thick-enough masses to suppress all but the most ruthless of weeds.

      Each leaf, which is about 45cm (18in) long and 1cm (½in) wide, is bright, shiny green with a narrow band of white along both edges. An occasional wispy filament appears along the length. Foliage is produced in substantial amounts to form dense mounds around 30cm (1ft) high. Flowers appear in summer, but as they’re insignificant brown offerings, they can be chopped off.

      Although Luzula sylvatica ‘Marginata’ is evergreen, clumps can start to look a bit scruffy after a few years and benefit from being chopped down to ground level with a pair of shears. This will encourage new shoots to regenerate from the base.

      This is a very easy plant to cultivate, as it will grow practically anywhere and can tolerate a wide range of conditions. However, if subjected to too much stress caused by infrequent watering or by baking in too much sun, it is more likely to suffer from rust disease. Well-fed plants that are regularly watered and grown in fertile soil are much more capable of shrugging off this unsightly discoloration. Instead of spending time spraying affected foliage, cut it all back to the base and let it start again. Improved care should prevent the disease from returning the next season.

      Light woodland shade will provide the richest-coloured foliage. Any soil will do, but a well-drained loamy one would be best. For optimum results, keep the soil fairly moist, but avoid making the ground too boggy. An annual dose of well-rotted manure in spring gives excellent results. Propagation is easy to do by dividing up existing clumps with a sharp knife.

      Apart from rust disease, little else seems to cause this grass any problems.

       Miscanthus sinensis Gracillimus’

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      Miscanthus sinensis ‘Gracillimus’ is grand enough to be planted as a single specimen in a focal position in the garden.

      A delicate-looking oriental grass made up of lots of narrow leaves that arch over gracefully to form a dense clump. The overall height is around 90–120cm (3–4ft). The leaf edges are slightly serrated, making them rough to the touch and sharp enough to cut the skin if you pull them through your hands. They are sage-green in colour with a barely noticeable white stripe running along the centre. These grasses bulk up fairly quickly – a five-year-old plant could fill a circle 90cm (3ft) in diameter.

      At the end of a hot summer, pretty tufts of reddish grassy flowers appear, reaching up to just above the foliage. These last many weeks. Soon after flowering, the foliage starts to change colour, taking on various red or bronzy hues until it turns yellow and brown. At this stage, it is best cut down to ground level for winter. New growth starts early the following