<em>Hakonechloa</em>, herb of Japan: planting, cultivation, care

Description and botany

Hakonechloa takes its name from its region of origin. This grass naturally grows on rocky slopes of Japan’s main island, in Mount Hakone region. Its native habitat shows that Japanese forest grass, known as ‘Hakone Grass’ in English, prefers fresh but well-drained soil rich in humus. It can, however, grow in slightly clayey, heavy soil if this remains cool. Leaf colouration (especially autumn) is more intense in sunnier positions. Hakonechloa also tolerates shade, dappled light being ideal.

This perennial belongs to family Poaceae (grasses), like Miscanthus, Stipa, Pennisetum. Hakonechloa is monospecific — there is in fact only one species, Hakonechloa macra — but several cultivars have been produced by hybridization, offering a range of very decorative leaf colours, such as Hakonechloa macra ‘All Gold’, or with attractive variegation, such as Hakonechloa macra ‘Aureola’.

All display linear leaves, borne on culms with a pendulous habit forming tufts that reach around 30 cm, sometimes more after a few years, and up to 50 cm for type species, the most vigorous, Hakonechloa macra.

Its supple habit gives impression of a large cushion cascading like a waterfall. This Japanese spreads gracefully in a series of successive waves. Growth is fairly slow and takes a few years to reach full potential.

In autumn, foliage gradually changes colour. Some Japanese forest grasses adopt golden tones while others, such as Hakonechloa macra ‘Nicolas’, display bronze to orange shades.

Foliage of Hakonechloas is elegant and decorative: H. macra, H. macra ‘Aureola’, H. macra ‘All Gold’ and H. macra ‘Naomi’

Like many grasses with marcescent foliage, Hakonechloa remains decorative for part of winter.

Watch Hakonechloa macra ‘All Gold’ in video :

Different varieties of Hakonechloa

Hakonechloas with solid foliage

Hakonechloas with variegated foliage

Hakonechloas with coloured foliage

Hakonechloa macra - Japanese Forest Grass

Type species. More robust, more drought-resistant, also most luxuriant. Forms an elegant dome of solid green that can dress shaded banks.

• Flowering time September, October
• Height at maturity 40 cm

See the product sheet

Hakonechloa macra All Gold - Japanese Forest Grass

Brightest, most luminous variety! Its entirely golden foliage stands out from afar. Placed in a large blue pot with matching rounded shape, it looks wonderful on a shaded terrace.

• Flowering time September
• Height at maturity 40 cm

See the product sheet

Hakonechloa macra Aureola - Japanese Forest Grass

Perhaps most popular variegated variety. Its elegant yellow foliage, striate with dark green lines, is very luminous in shade. It can take decidedly golden hues in autumn.

• Flowering time August, September
• Height at maturity 30 cm

See the product sheet

Hakonechloa macra Albostriata - Japanese Forest Grass

Green foliage streaked with white or cream striations. An elegant, understated variety that will sit perfectly at the foot of trees, under dappled light.

• Flowering time September, October
• Height at maturity 40 cm

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Hakonechloa macra Beni-Kaze - Japanese Forest Grass

A fashionable cultivar! Its graphic, airy foliage displays a lovely green throughout the season then gradually colours until becoming entirely purple-red in autumn.

• Flowering time August, September
• Height at maturity 50 cm

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Hakonechloa macra Sunflare - Japanese Forest Grass

Recent mutation of 'All Gold' variety, it offers equally yellow, luminous foliage whose tips gradually flush red during the season. It finishes beautifully in autumn with superb golden, orange and purple hues.

• Flowering time August, September
• Height at maturity 40 cm

See the product sheet

Hakonechloa macra Naomi - Japanese Forest Grass

Its golden-green foliage early in the season turns purple in autumn. Slightly less vigorous, it makes a striking pot specimen on a cool terrace or balcony.

• Flowering time August, September
• Height at maturity 40 cm

See the product sheet

Hakonechloa macra Nicolas - Japanese Forest Grass

A superb variety with autumn colours ranging from gold through orange to bronze. Placed near other plants with fine late-season colours, it will serve both as backdrop and highlight.

• Flowering time July to October
• Height at maturity 40 cm

See the product sheet

Planting Hakonechloa

Where to plant hakonechloas?

Shade and partial-shade perennial, plant these Japanese grasses at the foot of trees and bushes to provide beneficial cover from scorching sun rays during warm season. Hakonechloas will appreciate cool banks, bright understoreys and forest edges. North of Loire, they can more easily tolerate growing in sun, provided soil remains cool.

They can also punctuate borders or mark corners, softening them. Near a water feature, they enhance, with their fountain habit, sense of freshness while benefiting from ambient humidity.

Fountain habit of Japanese grass also contrasts beautifully with more mineral surroundings. For mass effect or large waves, plant 4 to 6 plants per m².

Hakonechloa primarily prefers soils that retain good moisture levels, ensuring generous leaf development and lovely colours. Light, neutral or acidic substrates rich in humus ensure healthy growth in opulent cushions that smother weeds. It can, however, grow in heavier clay soils, provided its rootstock does not lack water.

Japanese forest grass can also easily adorn balconies and terraces. It is well suited to container culture. While a few hours of sun, early or late in day for example, help bring out best colours, avoid south-facing exposures where excessive heat causes suffering. In general, variegated or golden varieties (such as Hakonechloa macra aureola or Hakonechloa macra ‘All Gold’) prefer shade. Others, such as Hakonechloa macra ‘Nicolas’, benefit from a brighter but not scorching exposure to better show their colours.

In all cases, their slow growth asks gardener for some patience to fully enjoy their unique graphic appeal.

→ Also discover our advice sheet on slow-to-establish plants

Hakonechloa macra ‘Naomi’ by a water feature

When to plant?

Best planting period for Hakonechloa is early spring.

How to plant?

Planting in ground:

1. Immerse bucket so rootball becomes thoroughly moist. Meanwhile, prepare soil.
2. Turn and crumble soil to spade-depth and about forty centimetres square.
3. Amend with a shovelful of well-rotted compost and a handful of decomposed manure. You can also add a handful of base organic fertiliser rich in nitrogen, such as blood-and-bone or horn meal. Its slow breakdown promotes good rooting and feeds soil long-term. Foliage will find nitrogen for healthy development. Lighten heavy soils with river sand.
4. Backfill hole with this mix then dig by hand a planting hole to slip young plant into. Top of rootball should be level with soil.
5. Firm with hand without over-compacting and water abundantly, even if it rains! Especially at start, continue watering according to weather and chosen exposure.
6. Apply mulch (dead leaves or ramial chipped wood for example) about 5 cm thick around base to retain coolness and encourage Hakonechloa to spread. Choose mineral mulch (gravel, slate chips, sand…) according to atmosphere you want to create.

Planting in pot:

1. Immerse bucket in tub or bucket of water until rootball is saturated.
2. Meanwhile, after placing a good drainage layer, fill pot with good garden soil or rich compost-based potting mix (add compost if needed) to which you have added a handful of horn meal. Use of water-retaining crystals can be useful because soil dries faster in pot than in ground (follow dosages on packaging). Substrate should sit about 5 cm from top of container.
3. Set young plant in centre of pot, firm lightly and water gently in small quantities until water drains from holes.
4. Apply light mineral mulch (gravel, sand, fine slate chips…) which keeps soil cool, limits competitor plants and adds decorative effect. Do not use heavy or bulky materials (large pebbles) or thick coverings (fabric, plastic…)

Ensure afterwards that substrate never completely dries out. Use of saucer creates, in warm season, a beneficial water reserve. In winter, empty saucer. Choose pots large enough to let Japanese forest grass develop freely.

→ Learn more with our advice sheet: Growing a Hakonechloa in a pot

Care

Like many grasses, Hakonechloa macra requires little care for maximum decorative effect.

Your only real task is to ensure soil stays consistently moist.

For everything else, only one annual intervention is necessary, at the end of winter: cut back all dead stems to about 3 to 5 cm above soil.

Add a handful of compost to nourish the plant properly.

If grown in a pot, proceed in the same way. After a few years you will need to repot it and replace the substrate. This is also necessary if Hakonechloa has become too large and the pot too small.

Blaze of foliage of Hakonechloa ‘Nicolas’ in autumn / Hakonechloa ‘Aureola’ foliage still decorative in winter

Multiply

If you wish to multiply it, do so from an established clump, and be sure to carry out the operation in spring. Emergence of new shoots gives you the green light. The only reliable way to multiply your Hakonechloa plants is clump division.

Stump division

To divide a young plant of Hakonchloa:

1. Cut back dried foliage, take a sharp spade, lift out the stump and divide it into several pieces.
2. Replant them immediately and water
3. In a pot, lift out the Hakonechloa and divide it into several pieces. If using the same pot, remember to change the growing medium before replanting, then mulch and water.

Pairing Hakonechloa with other plants in the garden

Hakonechloa is a superb ornamental grass that grows equally well in a pot or in the ground. For pot choice, follow your inspiration. Bear in mind that the golden foliage of Hakonechloa macra ‘All Gold’ will, for example, contrast beautifully with a deep-blue pot. Ideal planted alone to adorn a corner of a patio, a terrace or a balcony with a cool atmosphere. Place at centre of a large pot an Imperata cyclindrica ‘Red Baron’ with upright red foliage surrounded by Hakonechloas. Guaranteed effect!

Several pots allow a pit with languid, soothing shapes, rocked by the wind.

Hakonechloas lend themselves well to container culture: Hakonechloa macra ‘Beni Kaze’

Growing conditions favoured by Japanese forest grass suit a wide range of other plants, so there are many ways to combine them.

Plant at base of handsome trees or bushes with clear trunks to serve as a setting and include it safely in compositions that match many styles.

Understated atmosphere: focus on foliage!

Foliage of Hakonechloa, besides being attractive, combines beautifully with other shade plants with decorative foliage. Play with shades of green, contrasts of form and texture, or create colourful contrasts. A bed designed this way can easily be as attractive as a flower bed.

Imagine a bed covered with a close carpet of Helxine of incomparable softness from which one or more clumps of Hakonechloas emerge. At rear, place a Japanese maple, perhaps one with purple foliage such as Acer palmatum dissectum ‘Garnet’. A contrast of tones and shapes that is always a safe choice.

Create an opulent effect with huge exotic leaves of a Gunnera maticata or a Tetrapanax, or the leaves of a Fatsia japonica ‘Spider’s Web’ with green splashed with cream-white. If space is limited, choose a more modest-sized Rodgersia.

Example of an understorey foliage combination: Hakonechloa macra, Ligularia dentata, Ferns (Dryopteris affinis, Dryopteris filix-mas, Dryopteris wallichiana…) and various Hostas

Shiny, tough, evergreen leaves of a Pachysandra provide a permanent backdrop.

Reinforce graphic effect with delicate-design fronds of ferns such as Athyrium nipponicum pictum whose foliage reflects beautiful metallic sheens, or the bold foliage of a hosta.

Create strong graphic echoes with clumps of Ophiopogon or introduce an oriental touch with bamboos and, if shade is not too dense, a Nandina domestica, the famous ‘Sacred Bamboo’.

Let a Pieris finish the planting and add a discreet floral note. Shapes, sizes, textures and colours of foliage provide long-term interest, but you can of course add some bulbs to mark spring.

Punchy atmosphere: dare colour!

Japanese forest grass offers foliage that works with a wide diversity of perennials or flowering bushes. It sets off its neighbours, links different colours and serves as punctuation to create rhythm for much of the year.

Many spreading groundcovers enjoy edge or light-woodland situations. Ajuga brings a blue or pink touch between May and June, on foliage you can choose green or purplish. Some Lamiums offer silver-toned foliage adorned in spring or summer with white, yellow or pink flowers, very luminous in less-exposed parts of the garden. Epimediums come in a wide palette of colours, both foliage and flowers. Be tempted by Farfugium japonicum with daisy-like yellow flowers in autumn.

A bright pairing idea: Hakonechloa macra ‘All Gold’, Rosa ‘Queen of Sweden’, Heuchera sanguinea ‘Leuchtkäfer’, Cirsium japonicum ‘Rose Beauty’ and foliage of Cimicifuga simplex ‘James Compton‘ which will flower later in season.

For bush choices, opt for a Daphne whose scent enchants in mid-winter, or a Hydrangea to add colour mid-season.

Rely on flowering from hellebores, alchemillas, aquilegias and foxgloves, not forgetting perennial geraniums such as Geranium nodosum, which return reliably each year.

Dare an Amsonia hubrichtii with fine foliage that takes lovely autumn tones. If experienced gardener, try Cardiocrinum giganteum whose large lily-like flowers open up to 2 m high in summer. Many other spring bulbs or summer bulbs add extra colour. Prefer orchid-like flowers? Choose Tricyrtis for jewel-like blooms late summer.

Also consider Hakonechloa in mineral-themed schemes. It can either emphasise curves or soften austerity of stone elements.

→ Discover our ideas for combining Hakonechloa

Did you know?

Poacées occur on all continents worldwide, including the coldest regions such as Antarctica. They grow in very different habitats, from the driest to the wettest, and represent on their own an astonishing diversity with more than 12,000 species identified to date. Poacées are among the most diverse plant families, behind Orchidacées, Astéracées and Fabacées (formerly legumes).

The word ‘grass’ is often used to group together a number of plants that look similar but are not all Poacées. This is the case for Carex (Cypéracée) or luzule (Joncassée), for example.

The term ‘grass’, which today should be replaced by Poacée, has thus entered common vocabulary. It is still commonly used by many gardeners and nurserymen to refer to plants that therefore do not all belong to family Poacées.