The magic of winter grasses and top tips for growing them in the garden
There’s midwinter magic in the air, because the sun is lower in the sky than at any other time of the year. It’s slanting through the garden, highlighting texture and detail, and taller grasses are stealing the limelight. It may be raindrops glistening along the length of the stems, or upright plumes getting the William Holman Hunt Light of the World treatment, or feathery silhouettes shimmying and swaying in the slightest breeze. They certainly do that in my hilltop garden and, as winter unfolds, the grassy heads disintegrate and form a gauzy haze as they dance to the tempo of each day, from fast foxtrot to slow waltz.
They’re an essential and much-loved part of my winter garden, but mention grasses to many a gardener and you can see a shutter coming down, plus a slight tightening of the jaw. People are suspicious, to put it mildly. Perhaps they’re dedicated to putting their gardens to bed every September, or they might be haunted by the memory of planting a variegated thug called gardener’s garters (Phalaris arundinacea ‘Picta’). This 1970s nightmare was wont to travel into neighbours’ gardens and beyond, but nowadays there are lots of good-mannered, clump-forming grasses that make winter special.
The skill lies picking the right one, because many of the best late-season grasses are at the northern edge of their range. I’m in the heart of England, consequently my grasses perform six weeks later than in the banana belt of southern England, or in the milder western half of the UK. Also, many pennisetums and all panicums struggle with me, because my garden’s too cold. Friends in Hampshire and Kent glory in them.
The best miscanthus
Arguably the best clump-forming winter grass is Miscanthus sinensis, and I would always advise planting the variety ‘Silberfeder’. This seven-foot high 1950s German variety, raised by Hans Simon, is guaranteed to flower for everyone. In my garden the silvery plumes appear by the end of August or beginning of September, late enough to persist through winter.
Miscanthus sinensis comes in varied forms, heights and colours, as an off-site trial held at RHS Wisley 20 years ago demonstrated. Some grassy panicles open to deep wine-red, before fading to mink-brown after a month.
‘Ferne Osten’ AGM is my red-blooded choice, because it’s willing to produce its flowers earlier and I find it less floppy than ‘Flamingo’. ‘China’ is similar, but has proved harder to grow for me here. The upright ‘Ghana’ combines red heads with burgundy-red foliage from late summer onwards.
Three others rise above the pack. ‘Graziella’ has long stems topped with winter-white ostrich-feather heads that gracefully bend to one side. ‘Malepartus’ flowers four weeks earlier, with red ostrich feathers that turn buff-pink. The lusher silver-striped foliage develops shades of marmalade as temperatures cool. If it’s fine foliage you’re after, ‘Gracillimus’ should be your choice, although the copper-red inflorescences arrive late.
Some miscanthus are grown for their foliage rather than seedheads, but they also make an impact in the winter garden. ‘Morning Light’ graced Japanese gardens for centuries, before being introduced in the mid-1970s. The finely lined foliage makes a slim, upright sheath of modest metre-high proportions and it’s effective woven through an autumn border.
All together showier is ‘Cosmopolitan’, a statement plant. The wide green and white horizontally striped leaves make a year-round feature, with cream-edged green foliage decorated with a pale midrib.
‘Cabaret’ is even showier, although the variegation is reversed, with cream-white leaves banded in dark green. Both were introduced from Japan, so need warmth to perform well. Both rarely flower here.
Miscanthus nepalensis, my favourite Afghan hound of a grass, needs Himalayan conditions, namely good drainage in winter and plentiful rainfall in early summer. This is one grass that benefits from a mulch of coarse grit and the watering can.
Prizes for pampas
Grasses are not new kids on the block. In The English Flower Garden of 1883 William Robinson (1838-1935) described miscanthus as a Prince of Wales feather. He also rated ‘Zebrinus’ – this is far more pleasing than the upright ‘Strictus’, which lacks any sort of flow or grace.
Robinson, an exponent of wild gardening, is also credited with planting the first pampas grass (Cortaderia selloana) in Regent’s Park, shortly after he arrived from Dublin in 1861. This South American grass is completely underrated: the upright plumes shine in late autumn and winter, providing a series of exclamation marks. They can get shabby, following a cold winter, but they recover well and there’s always a hibernating hedgehog underneath mine.
I was lucky enough to judge the RHS Wisley pampas grass trial (2007-2009), and I can still recall the plumes of the unfortunately named ‘Monstrosa’ defying the winter skies, without any hint of nicotine in its silver-white plumes. This will reach 2.5m (9ft) so it’s not for small plots.
‘Sunningdale Silver’ is equally tall, but it has far fluffier cream plumes. ‘Patagonia’ was distinctive on the trial, with tighter mink-brown heads. All three were awarded the top honour, an AGM.
Shorter AGM varieties, rising to five feet or 1.5m, include ‘Pumila’ and I’m grateful that I saw a variegated sport named ‘Silver Feather’ on this trial. It arose at Nottcutts Nursery in Suffolk and mine has been in the ground for 12 years. More than 100 garden-reviving plumes appear in late September or early October and splay gently outwards - winter torches under moonlight.
The trial also introduced me to a New Zealand cousin, Cortaderia richardii, which is summer-flowering, even for me. It’s known as toe toe grass, but pronounced toy toy I’m told. Forms vary, but this graceful shimmier makes a great back of the border plant and, by the time winter arrives, the arching heads have been eroded to skeletal remains. The downside, in gardens warmer than mine, may be unwanted seedlings.
Vibrant verticals
It’s vital to have upright skyrockets to provide vertical accents. The ultra-reliable Calamagrostis x acutiflora ‘Karl Foerster’, the feather-reed grass, produces a sheath of vivid green foliage and tightly packed stems topped by narrow heads in summer. When new, these stems can break at the node so some shelter is advised. It’s a perfect backbone plant, repeated along the spine of a border. As winter descends, the sheath colours up and, in more southerly gardens, it gets bleached to winter white. It was named after the German nurseryman and landscape architect who thought of grasses as nature’s hair.
Molinias also linger into winter, although few make it all the way through to the bitter end because they produce their flowery heads in summer. Once the New Year arrives, it’s out with the secateurs. The tall ones have subsp. arundinacea in their Latin name. Tim Fuller’s Norfolk Nursery, The Plantsman’s Preference, holds the Plant Heritage Collection and the customer favourite is ‘Transparent’, a finely beaded grass that I partner with Ratibida pinnata, a drooping yellow daisy. The best autumn colour award goes to ‘Zuneigung’, because it turns rich orange. Tim also rates a new Belgium-bred variegated molinia named ‘Mostenveld’ as well as ‘Skyracer’. All molinias prefer full sun and good soil. They splay their stems outwards above a low mound of foliage, displaying lots of stem.
Perfect pennisetums
Pennisetums provide curtseying fine foliage that cascades like gently breaking waves, softening corners and edges. The flower heads are usually fuzzy bear caterpillars; these have a gossamer presence in low sunlight and, when it rains, the tiny bristles catch micro droplets that glisten. The go-to species for winter hardiness is the Asian P. alopecuroides ‘Hameln’ is the established landscape choice, with beige heads above foliage that turns to amber when temperatures cool.
There are more exciting choices. You get redder foliage and darker caterpillars with ‘Cassian’s Choice’; this was used with the seedpods of Amsonia illustris in Charlotte Harris’s and Hugo Bugg’s M&G garden at this year’s Chelsea Flower Show. I also have a lot of time for the slender pink heads of ‘Karley Rose’, which coincide with pink echinaceas here. You can also seed-raise P. macrourum, although it’s more worm than caterpillar.
The recent ‘Fairy Tales’, a hybrid cross of unknown parentage, was introduced from California by Neil Lucas of Knoll Gardens. He rates it for its long flowering habit and more upright stance, although heavy autumnal dews do bow the heads to great effect. Plant hardiness is more about winter wet than cold temperatures, so a garden hot spot is need for pennisetums.
Panicums are a step too far for many British gardeners, because they thrive in hot summers and cold winters. They produce spikelets of flower and a fountain of foliage that spirals out from a tight waist. ‘Heavy Metal’ combines blue foliage and pink spikelets. ‘Dallas Blues’ has purple-pink heads and even bluer stems. I covet these, but to no avail.
Top tips for winter grasses
⇒ Buy from a specialist nursery. The naming is reliable and the range far wider.
⇒ Plant in a bright position that catches the sun.
⇒ If you want a clump, plant three in a triangle and they will join up.
⇒ Splitting grasses is best done as they start into life in the spring, but only divide them if needed – eg if there’s a dead spot in the middle.
⇒ Grasses have great spring foliage as well. Miscanthus sinensis is often interplanted with tulips.
⇒ Cut the toughies back in early spring, in February if possible, because many shoot into new growth early. Wear stout gloves, because you can get lots of cuts. Pampas grass is the worst!
Excellent planting partners for bleached winter grasses:
⇒ Cotinus coggygria ‘Royal Purple’, a wine-leaved shrub, hangs on to its foliage late, adding a colourful infusion to bleached grasses. The faded flowers match the grasses in texture.
⇒ Self-supporting tall, dark-leaved and -stemmed asters, such as Symphyotrichum laeve ‘Calliope’ and ‘Glow in the Dark’ shine against fading grasses late into the year.
⇒ Pink-headed miscanthus varieties chime with the maroon clouds of Eupatorium maculatum ‘Riesenschirm’ behind the stately Sedum ‘Matrona’.
⇒ The royal-blue aconitum ‘Arendsii’ flowers late enough to stand out next to silver-plumed grasses. Kniphofia rooperii, a late-flowering orange poker, can complete the trio.
⇒ Tall, see-through, darkly bobbled sanguisorbas, such as ‘Red Thunder’ and ‘Martin’s Mulberry’, add definition.
⇒ Veronicastrums look right with grasses: ‘Red Arrows’ (it’s actually purple) and the pink ‘Erica’ produce tapered seed heads
Suppliers
⇒ The Plantsman’s Preference (plantpref.co.uk; 01379 710810)
⇒ Knoll Gardens (knollgardens.co.uk; 01202 873931)
This article is kept updated with the latest information.
