Читать книгу Architectural Plants - Christine Shaw - Страница 15
ОглавлениеGrasses are currently enjoying immense popularity, but few could really be described as architectural because of their poor winter performance, with many of them turning a horrid brown colour as soon as autumn approaches. However, the grasses selected for this chapter are definitely architectural.
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Cyperus papyrus is an essential addition to a large conservatory.
The following grasses are nearly all evergreen, thus creating a year-round presence wherever they are planted. They are all striking in some way, for example, Ophiopogon planiscapus ‘Nigrescens’ with its jet-black foliage or Cyperus papyrus with its tall stalks topped with huge fluffy tufts of flowers. And let’s not forget an old favourite, Cortaderia selloana, the lovely Pampas Grass that for years has been snootily ignored but, at last, is enjoying new fame as gardeners once again start to appreciate its stately appearance.
The two non-evergreen grasses featured are here because, despite their lack of winter appeal, the statuesque quality of Arundo donax and the shapely outline of Miscanthus sinensis ‘Gracillimus’ are just too wonderful to overlook. Their stunning good looks during three quarters of the year are compensation enough to earn their inclusion.
The grasses in this chapter have a wide range of shapes and sizes, from the diminutive Acorus gramineus ‘Variegata’ to the decorous Cortaderia richardii. Their cultural requirements vary hugely too, from the water-loving Cyperus alternifolius to the unfussy Luzula sylvatica ‘Marginata’.
One thing these grasses do all have in common is their ease of propagation. All of them grow as clump-forming plants and all can be divided up at almost any stage of maturity. The smaller grasses can have their clumps teased apart by hand. Some will need the help of a sharp knife and some with heftier root systems will need the assistance of a strong spade to chop through each section. The propagation of grasses is more down to brute force than expertise, and even novice gardeners are capable of achieving successful results.
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Cyperus alternifolius is a dainty grass, ideal for growing in and around ponds and streams.
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Cortaderia selloana is the famous Pampas Crass familiar to many gardeners.
Apart from the Cyperus grasses, all of the plants described here are fully hardy, capable of coping with temperatures down to -20°C (-4°F). So, almost any gardener can take advantage of their beauty, especially as their hardiness is combined with a robust nature and ability to cope with hostile conditions. Their individual requirements are discussed in each plant entry, but it will be noted that many can cope with exposed and windy conditions, making them good choices for gardens near the coast and for those on open hilltops. This group of plants is far more forgiving than their close relatives, the bamboos.
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Miscanthus sinensis ‘Gracillimus’ looks and sounds wonderful as the breeze swishes through it.
Grasses are the perfect group of plants for beginners, although experts appreciate their fine qualities too.
Grasses can fit in with many different kinds of planting schemes. The larger grasses look splendid enough planted as single specimens to spice up unexciting borders or to act as a soft backdrop to other plants. The smaller ones will look good anywhere in the garden, but avoid dotting just single specimens around.
The smaller grasses look far better, more noticeable, more effective and more dramatic if they are planted in drifts or large groups. In a small space, five of the same species of plant look a hundred times more natural and pleasing to the eye than one each of five different species, which can give a bitty and undisciplined look to a garden.
The maintenance of most grasses is easy too, providing their individual needs have been catered for, and most are happy with a light annual dressing of blood, fish and bone in early spring. Older clumps can become a bit tatty and tired-looking after a few years. If this happens, they can be rejuvenated quite easily. Many can be hacked back to ground level with a sharp pair of shears in the autumn or early spring. This may sound a drastic thing to do, but you will be rewarded by a vigorous burst of new fresh foliage as soon as the new growing season commences. By the end of the season, a completely new clump will have formed. The remaining bases of the old foliage will, by this time, have dried out and gathered as a brown thatch throughout the bottom of the new leaves. This can be teased out by hand to keep everything looking fresh and tidy.
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Luzula sylvatica ‘Marginata’ has a very forgiving nature, making it a good choice for beginners.
Acorus gramineus Variegatus’
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A pretty little grass for ponds or boggy areas.
For those gardeners who like their plants neat, tidy and compact, this tiny Japanese grass would fit the bill admirably. It reaches no more than about 25cm (10in) in height. It grows in fan-shaped sections, consisting of many individual blades of grass closely packed together. Gradually, these clumps bulk up and spread quite slowly to cover a distance of around 60cm (2ft) across. Each of these sections can be removed at any time of the year and used for propagation.
The grassy leaf blades are vertically striped with green and pale cream. The variegation is pleasantly subtle and, unlike many coloured-leaved plants, is not at all offensive to look at. Mature plants sometimes produce flowers, particularly during very warm weather. These are long and narrow and can be quite difficult to see, as they are the same colour as the cream bits on the foliage.
This plant is ideal for any moist or boggy spot in the garden. It loves moisture so much that it is even quite happy in a shallow pond, and makes a useful aquatic addition to water features and streams. It is fully evergreen and as attractive in winter as it is in summer. As it is very slow-growing, it could be grown in a pot for the first few years of its life, but remembering to water it virtually every day could become too much of a chore. This grass is too small to be grown as a single specimen and needs to be in larger groups for maximum impact.
Full sun will give the best colouring, but light shade is quite acceptable. It will grow in any soil, but rich loam would give the best results. It must always be kept moist – it is almost impossible to overwater. Remove any older leaves as they turn brown. Apart from the odd aphid, this plant is usually trouble-free.
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.
Arundo donax
Spanish Reed
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The large canes of Arundo donax make a fantastic sound in windy weather.
A huge grass that looks a bit like sugar cane. It can grow to 4m (13ft) tall and has thick canes a good 3cm (1in) in diameter. The long, narrow blue-green leaves can be up to 60cm (2ft) long. It is probably the most dramatic inhabitant of the grass world that can be grown in temperate climates. Its energy goes into producing height, rather than width, and it is quite slow to bulk up enough to form a decent-sized clump. Unless you’re very patient, plant at least three of these grasses together to speed up the effect.
The flowers are pale creamy brown, feathery plumes. They are a lovely bonus to growing this grass, but they seem to appear only on plants in warmer European countries such as Spain or Italy, where they are widespread.
Arundo donax is very hardy and is especially useful in coastal areas. Despite its stature, it can stand up to sea winds extremely well and, in a strong breeze, the leaves whip around the canes making a wonderful noise. It is a good choice for planting as a windbreak in exposed seaside gardens.
A variegated form is often available with pale cream stripes along the leaves. This is less hardy than the straight green form and reaches only 2.2m (7ft) in height. It is even slower to form decent-sized clumps than its green counterpart, and should therefore be planted in more generous groupings.
Plant in rich, moist soil for the fastest growth, although any soil would suffice. It is happy in either sun or shade, but the variegated form prefers more sun to keep the colouring brighter. Moisture is the main requirement, and watering should be done regularly for the first couple of seasons after planting. After this time, Arundo donax is quite capable of fending for itself, and feeding and watering can be dispensed with. Generally, this grass will grow almost anywhere. It is often seen in water-filled ditches and along riverbanks throughout Europe. But, it can also cope with the other extreme, tolerating sun-baked clay soil without much of a problem.
If the soil is very poor and growth is unsatisfactory, apply a good helping of blood, fish and bone in the spring. Well-rotted manure will also help speed up the growth rate. Very little maintenance is required, apart from the removal of any brown leaves as they appear.
During the winter, the leaves turn brown and two choices can be made. Either cut the whole lot down to ground level, from where it will start to regrow in spring, quickly reaching its full height again in one season. Or, strip the foliage from the stems, to leave just the bare canes. This latter method has two advantages. Firstly, the space that the plants occupy won’t be completely empty in the winter, and lots of bare stems are definitely much more attractive than a gap in the planting scheme. Secondly, during the following growing season, new canes will not only emerge from ground level, but side shoots from the old canes will also sprout, making an even bushier clump.
Pests and diseases are not usually a problem. Propagation can be done by dividing up existing clumps with a spade, by stem cuttings grown in water or from fresh seed.
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In warmer climates, the flowery plumes of Arundo donax soar above the foliage.
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The variegated version is smaller and less hardy.
Cortaderia richardii
Toe-Toe
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Cortaderia richardii is a brilliant plant for coastal gardens.
This gorgeous grass is similar in many ways to the well-known Pampas Grass. But, instead of originating from South America, it hails from New Zealand, hence its Maori common name of toe-toe, which is actually pronounced ‘toy-toy’.
Masses of long, grassy blades form great heaps of foliage that eventually reach dimensions of around 1.5m (5ft) in height and the same size across. Each blade is slightly serrated along the edges, enough to cause some discomfort if grabbed and pulled through your hands as you walk by. During the winter, this plant stays much greener than many grasses, making it highly attractive for the entire year.
The plumes of grassy flowers are also similar to the more familiar Pampas Grass, but those on this grass are sent up during mid-summer instead of early autumn. They are shorter and a much nicer colour – a kind of bronzy-beige. They are lovely and fluffy, and can be cut off for using in dried flower arrangements, where they look good for many months until they start to gather dust.
Cortaderia richardii is a very easy plant to cultivate. It is largely unfussy, although it hates being in the shade. It makes a good coastal plant, as salty winds do not seem to cause any harm. However, it stays much tidier if grown tucked out of the way from the. strongest sea breezes. Good light levels are required – the more sunshine, the better. Most soils are fine, although the very best results will be from rich, moist loam. If the soil is very poor, enrich it annually in spring with a large dollop of well-rotted manure.
Moist conditions are preferred but, once established, much drier conditions can be tolerated, and watering is usually necessary only if the summer is excessively rain-free. Water regularly for its first season after planting until the roots have settled in.
Remove any old brown leaves and cut off the flower spikes when they become scruffy. Chop these off with secateurs as low as you can reach down into the centre of the plant.
Pests and diseases do not often cause any problems. Propagation can be by division or from fresh seed.
Cortaderia selloana
Pampas Crass
SYN. Cortaderia argentea
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After being snootily ignored for years, this lovely grass is at last being planted again by gardeners.
The ‘prawn cocktail’ of horticulture is how some gardeners describe Cortaderia selloana, but this seems to be very dismissive of a wonderful grass.
It can form massive clumps of glaucous green that make an imposing addition to any garden. Mature clumps can reach 2.5m (8ft) tall and 3m (10ft) across. Enormous quantities of long, arching evergreen leaves quickly pile up on themselves to form a graceful architectural shape. Each slender leaf blade is sharply edged along the entire length. The sharp bits are too small to be seen, but can be painfully experienced if you pull the leaves through your hands. In late summer, tall panicles start to emerge from the centre of mature plants. These can reach 3m (10ft) tall and open out into large fluffy plumes of a rich cream colour. They last for most of the autumn. They can be left on the plant to be enjoyed, or be cut and dried for indoor flower arrangements.
This is a very easy plant to grow and it is forgiving of most planting sites. However, it would prefer to be in a bright sunny planting position, sheltered away from strong winds. The soil should, ideally, be a rich loam, but most types will give adequate results. Really poor soil can be fed annually with any high nitrogen food in the spring. Water regularly until established. After the first couple of seasons, it can usually take care of itself.
Older clumps that become untidy can be given a savage haircut every few years in early spring. Cut the entire clump down to ground level with powerful electric hedge-cutters.
If this becomes too difficult, an alternative method is to set fire to the whole lot and burn it down. This quickly deals with all the brown thatch that gradually accumulates from old leaves. New foliage soon grows up again.
There are various coloured forms available but none manages to match the splendour of the true Pampas Crass. Propagation can be done by division and also from seed, but seed-grown plants can be very variable in habit and colour. A particularly good cultivar is ‘Sunningdale Silver’, which has beautifully pale plumes. Cortaderia selloana ‘Pumila’, a dwarf form, is a wonderfully stubby half-sized version for small gardens.
Pests and diseases rarely bother this grass.
Cyperus alternifolius
Dwarf Papyrus
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Although this grass is native to Madagascar, it can be grown successfully in much cooler climates.
A pretty little perennial grass that resembles a miniature Papyrus, but is much tougher. It is reliably hardy, though, only in mild inner city gardens and coastal areas. It forms clumps of long, bright green stalks that can reach 90—120cm (3–4ft) tall. These are topped with spreading ‘umbrellas’ of grass, so that the whole plant looks like tiny palm trees. The flowers are typical grassy tufts and not terribly exciting.
Outdoors, grow it either in a pond or a very boggy 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 season, and the fresh green shoots soon reach their full height. There is only a short period of time, just a few weeks, when this grass is doing nothing of interest.
Miscanthus sinensis ‘Gracillimus’ is a very easy plant to cultivate and will grow just about anywhere. It can cope with clay, peat or chalk. For the very best results, however, grow it in fertile, loamy soil that stays moist at all times, without ever becoming boggy. It prefers a sunny position. Watering is more important for the first couple of seasons after planting. Mature plants that have become established can usually fend for themselves.
This grass can cope with windy positions quite well, but avoid really exposed sites, where strong winds can leave it looking decidedly battered. It doesn’t mind salty air, so is a good choice for seaside gardens. This is a versatile plant that looks good in all sorts of gardens: it can add structure to herbaceous borders, looks marvellous when planted with other grasses, and is large enough to be planted as a specimen plant in a focal part of the garden.
An annual feed can be given in spring, if desired. Use a light helping of blood, fish and bone sprinkled around its base. There is little other maintenance to worry about, and pests and diseases are not usually a problem.
Propagation is by division, which can be done in spring when the new shoots are just bursting into growth.
Ophiopogon planiscapus ‘Nigrescens’
Black Crass
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This unusual-coloured grass is small and slow-growing, making it suitable for a pot.
The Latin name of this grass took me years to be able to pronounce fluently – it really makes you wonder who’s responsible sometimes ….
Despite its daft name, this splendid plant would please even the most design-conscious gardener. The leaves really are jet-black. They form tufts of coal-coloured clumps that spread slowly to cover areas of no more than around 90cm (3ft), with a maximum height of only 15cm (6in). Groups of this lovely grass look particularly effective in beds mulched with light-coloured grit or stones, to show off their deep colour fully. They also look best planted in large numbers – just dotting one or two around a garden would make them look a bit lost. In a local municipal planting scheme that I saw recently, a circular bed 2.5m (8ft) in diameter had been dug out of a lawn. In the centre was a small tree, and the rest of the space had been completely filled with nothing but this grass. The effect was wonderful.
Apart from the unusual-coloured foliage, this evergreen has attractive sprigs of lilac flowers in late summer, followed by small, shiny berries that last for months.
These Japanese plants perform best on light, well-drained soil. If the soil tends to be heavy, stir in some extra grit or silver sand to improve drainage. Full sun is preferred, but their colour holds well in light shade. Once established, they are remarkably drought-tolerant. Their size makes them a good choice for growing in a terracotta pot, but they are much slower to spread when grown this way than when they are planted directly into the ground.
This plant is very easy to cultivate and almost maintenance-free. Annual feeding is not really necessary, but a small amount of general fertilizer can be applied in spring, if you wish. Pests and diseases are not usually a problem, although aphids can sometimes be a nuisance in the summer, and regular inspections should be made for them.
Propagation is easy by division but, as these plants are so slow to spread, very little spare material is available for this purpose.
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The berries are jet-black, shiny beads.
