Monthly Musings

There’s something magical about September light. Colours look crystal clear, much richer than in summer, and the sun slants in at just the right level to create drama in the borders. This is when late-season grasses come into their own and they add another element or two - movement and texture. Most are tall and graceful and most move and sway with a gossamer presence. As autumn continues the texture of the awns, be it soft and fluffy or shiny and beaded, gets even more pronounced adding texture and form that lasts into winter.

Stance varies between a rocket-like stand of upright fine stems, to graceful long-stemmed feathers that fan outwards and upwards, to a curtseying sheath that nudges over the front of the border or lawn. Take note though. Many grasses grow at the edge of their range here, so in colder parts of Britain they will flower much later than they do in the south. This may influence your choice.

Miscanthus sinensis 'Zebrinus'

The King of the Autumn Grasses

Miscanthus sinensis stands supreme in the late-summer and autumn border, reaching somewhere between one and two metres. However some are grown for foliage alone and these include a subtle, yellow-banded, green-leaved miscanthus aptly named ‘Zebrinus’, or Zebra grass, because of its striped appearance. The stripes run across the leaf horizontally and are good at casting a light and shade pattern and this is precisely why Gertrude Jekyll (1843 - 1932) and William Robinson (1838- 1935) grew it under its old name of Eulalia japonica. A Japanese variety, that’s been around a long time, it rarely flowers but creates a good sheath of graceful, subtly banded foliage picking up the colour of tall yellow daisies, or acting as a foil for tall, late herbaceous.

William Robinson championed wild gardening and grasses, an antidote to colourful and ordered bedding schemes so beloved by his fellow Victorians. He’s thought to have been the first man to grow Pampas grass (Cortaderia selloana) in England, having planted it in Regent’s Park in London after seeing it at the National Botanic Gardens at Glasnevin near Dublin as a young gardener. These can be enormously tall, but Cortaderia selloana ‘Pumila' is a compact form rising to five or six feet only. The plumes appear in autumn and last through winter, forming exclamation marks in the border.

The craze for grasses took hold in Germany and their use was pioneered by a German landscape architect and nurseryman called Karl Foerster. He referred to grasses as nature’s hair and popularised them, but it was Ernst Pagels who began breeding them after working at Foerster’s nursery as a young man.

Miscanthus sinensis 'Morning Light'William Robinson also grew another miscanthus from Japan, which we now know as ‘Morning Light’. This has fine, light green foliage vertically banded and margined in cream-white, giving it a soft appearance in the garden. It’s a neat grass that makes a narrow clump, so it’s one of the best for a smaller garden. It will flower in warm years, but the flowers (should they decide to appear) are late and spidery with little substance.

Miscanthus sinensis was difficult to succeed with in the cold climate of northern Germany, much more so than in Britain, so Pagels set himself the task of raising earlier flowering ones that would perform. He persuaded ‘Gracillimus’, a refined miscanthus with a fountain of fine foliage that underpins airy flowers, to flower much earlier by growing it under glass. He collected and grew the seeds on. ‘Gracillimus’ was an inspired choice because this miscanthus develops a golden aura which flatters the thickly textured beige tassels.

Miscanthus sinensis 'Kleine Silberspinne'Pagels, who deliberately selected earlier flowering plants, produced some stunners. ‘Maleparetus’ is very similar to ‘Gracillimus’, but it will produce awns up to a month earlier. The finely banded foliage is topped with maroon-red upright awns by late summer. These age to pink, etched with silver. ‘Kleine Silberspinne’ (literally little silver spider) and ‘Kleine Fontäne’ (little fountain) were both bred by him. Both reach 1.5m and ‘Kleine Silberspinne’ has needle-like foliage and fine cockades in pink-red. ‘Kleine Fontäne’ is named because it produces a succession of slender, upright, red-toned silver flowers over several weeks. These red flowers, which look at their best in September light, quickly fade to snuff-brown and then to silver and gold.

Miscanthus make tight clumps and start into growth early on, and the easiest way to ensure a fresh stand of foliage is to cut them back hard in February so that they start all over again. Some gardeners use tulips amongst miscanthus because by the time the tulips flower in April and May, the foliage has developed into a lush, bright green mound.

Symphyotrichum 'Little Carlow'All taller grasses need equally tall perennials as partners to avoid the ‘Little and Large’ look, so the flowering ones, often called Prince of Wales feathers, associate well with taller perennials such as Veronicastrums, Sanguisorba ‘Red Thunder’, Helianthus ‘Lemon Queen', Symphyotrichum 'Little Carlow' and Aconitum carmichaelii (Wilsonii Group) ‘Spätlese’. This type of combination, tall grasses and late-season perennials, will often have winter presence for many months before they are cut back in February.

Molinias are very different, because they have a ruff of foliage at the base and long stems topped in heads that vary enormously from the fine beads of ‘Transparent’ to the more substantial heads of ‘Windspiel’ (literally wind’s game). These elegant grasses shimmy and shake and they make a wonderful veil towards the front of the border. Molinia caerulea subsp. caerulea ‘Heidebraut' (heather bride) is valued for it’s see-through stems and golden autumn colour.

American Switch grass, Panicum virgatum, needs warmth to flower well, so it’s not for colder gardens. If it does well for you, the Panic grass (named because the heads shake at the slightest movement), also needs good drainage. Foliage varies from the grey-leaved sheath of ‘Heavy Metal’ to the redder foliage of ‘Shenandoah’. The most attractive is ‘Rehbraun' which has green foliage topped by purple and green spikelets.

Pennisetum alopecuroides 'Hameln'Pagels, who deliberately selected earlier flowering plants, produced some stunners. ‘Maleparetus’ is very similar to ‘Gracillimus’, but it will produce awns up to a month earlier. The finely banded foliage is topped with maroon-red upright awns by late summer. These age to pink, etched with silver. ‘Kleine Silberspinne’ (literally little silver spider) and ‘Kleine Fontäne’ (little fountain) were both bred by him. Both reach 1.5m and ‘Kleine Silberspinne’ has needle-like foliage and fine cockades in pink-red. ‘Kleine Fontäne’ is named because it produces a succession of slender, upright, red-toned silver flowers over several weeks. These red flowers, which look at their best in September light, quickly fade to snuff-brown and then to silver and gold.

Calamagrostis bracytricha, the Korean feather reed grass, is an option for shade, with heather-pink, knee-high, silky awns that appear in late-August or September. Regular division every four or so years is needed to keep it vigorous, and this is done in spring, the best time to tackle dividing grasses.

Calamagrostis x acutiflora ‘Karl Foerster’ must be the world’s best architectural grass because the green foliage and dark awns, which appear in mid-June normally, age to a ramrod straight sheath of russet and gold. No other grass provides the same vertical presence and it forms the basis of many a prairie-style Piet Oudolf inspired border. It’s sterile, forms a tight clump and by September the awns begin to resemble narrow tapers.

Calamagrostis × acutiflora 'Karl Foerster'At the other end of the scale there’s the graceful Hakon grass (Hakonechloa) which flows over the edges like water so it can be used in containers, or close to steps, or in borders that retain moisture, or to soften a hard edge. It disappears underground in winter, although it’s very hardy, and reappears in spring. There are golden forms of Hakonechloa macra, such as ‘All Gold’ and garishly variegated ones such as ‘Alboaurea' and a cooler green and white named ‘Albovariegata' and they’re all good in shade as long as the soil stays moist.

If you’ve a wild garden, or a William Robinson streak for nature, a form of our native wood millet, Melica altissima ‘Alba’, is the prettiest thing among ferns in shade. The white beads of the flowers, no larger than a grain of rice, tremble and shake as daintily as a ballerina on points. Quite beguiling and completely different from any other grass.