<em>Hakonechloa</em>, Japanese herb: planting, cultivation, care

Description and Botany

Hakonechloa takes its name from its native region. This grass naturally grows on rocky slopes of Japan’s main island, in Mount Hakone region. Its native habitat shows that Japanese forest grass, called ‘Hakone Grass’ in English-speaking countries, prefers moist but well-drained soil rich in humus. It can, however, tolerate slightly clayey, heavy soil provided it remains cool. Leaf colour (especially autumn colour) is more intense in sunnier exposure. Hakonechloa also accepts shade; ideal conditions are dappled light.

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

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

Its graceful habit gives impression of a large cushion fallen in love with a waterfall. This Japanese grass spreads gracefully in a series of successive waves. Its growth is quite slow and requires a few years to reach its peak.

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

Foliage of Hakonechloa 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 through part of winter.

Watch video of Hakonechloa macra ‘All Gold’:

Different varieties of Hakonechloa

Hakonechloas with solid foliage

Hakonechloas with variegated foliage

Hakonechloas with coloured foliage

Hakonechloa macra - Japanese Forest Grass

This is the type species. Hardier and more drought-resistant, it is also the most opulent. It forms an elegant dome of solid green that can adorn shaded banks.

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

See the product sheet

Hakonechloa macra All Gold - Japanese Forest Grass

Brightest, most yellow variety! Its entirely golden foliage can be seen 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 the most popular variegated variety. Its elegant yellow foliage, striate with dark green lines, is very luminous in shade. It may take on distinctly golden hues in autumn.

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

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Hakonechloa macra Albostriata - Japanese Forest Grass

Green foliage with white or cream striate markings. An elegant, understated variety that will find its place at the base 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 shows a lovely green throughout the season before gradually colouring to become entirely purple-red in autumn.

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

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Hakonechloa macra Sunflare - Japanese Forest Grass

A recent mutation of the 'All Gold' variety, it offers foliage equally yellow and luminous, whose tips gradually take on red during the season. It finishes the season beautifully in autumn, displaying superb golden, orange and purplish tones.

• 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 is most attractive in a pot, on a terrace or a cool 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 golden to orange and bronze. Placed near other plants with fine late-season colours, it will act 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 base of trees and bushes to give them a beneficial cover from the sun’s scorching rays in warm weather. Hakonechloas will appreciate cool banks, light understorey and forest edges. North of the Loire, they can more easily tolerate growing in sun provided soil stays cool.

They can also punctuate borders or soften corners. Near a water feature, their fountain-like habit reinforces the impression of freshness while benefiting from ambient moisture.

Habit of Japanese forest grass also contrasts wonderfully with more mineral surroundings. For a mass effect or large waves, plant 4 to 6 plants per m².

Hakonechloa above all likes soils that retain good moisture, ensuring generous leaf development and beautiful colours. Light, neutral or acidic substrates rich in humus ensure good growth into opulent cushions that suppress weeds. It can, however, grow in heavier clay soils provided their rootstock do not lack water.

Japanese forest grass can also easily enhance balconies and terraces. It is well suited to container culture. A few hours’ sun, at start or end of day for example, will bring out best colours, but avoid south-facing exteriors where oppressive heat causes suffering. As a rule, 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 non-scorching exposure to better show their colours.

In all cases, their slow growth asks gardener for a little patience to fully enjoy their incomparable graphic appeal.

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

Hakonechloa macra ‘Naomi’ near a pond

When to plant?

Best time to plant Hakonechloa is early spring.

How to plant?

Planting in open ground :

1. Immerse the bucket to fully moisten the rootball. Meanwhile, prepare soil.
2. Turn over and crumble soil to depth of a spade blade and about forty centimetres all round.
3. Amend with a shovelful of well-rotted compost and a handful of decomposed manure. You can also add a handful of a base organic fertiliser rich in nitrogen, such as crushed horn. Its slow breakdown promotes good rooting and feeds soil long-term. Leaves will find in nitrogen what they need to develop. Lighten heavy soils with river sand.
4. Backfill hole with this mix then dig by hand a hole to slide the young plant in. Top of rootball must be level with soil.
5. Firm lightly with hand without overcompacting soil and water thoroughly, even if it is raining! Especially at the start, continue watering according to weather and chosen exposure.
6. Apply a mulch (dead leaves or ramial chipped wood for example) about 5 cm thick around base to conserve coolness and encourage Hakonechloa to spread. Choose a mineral mulch (gravel, slate chippings, sand…) according to atmosphere you want to create.

Planting in a pot :

1. Immerse the bucket in a basin or bucket of water until rootball is saturated.
2. Meanwhile, after placing a good drainage layer, fill pot with good garden soil or a rich potting compost (add compost if needed) to which you have added a handful of crushed horn. Use of water-retaining crystals can prove useful because soil dries faster in pots than in open ground (follow dosage instructions on pack). Substrate should come to about 5 cm from top of container.
3. Place young plant in centre of pot, firm lightly and water gently, in small amounts, until water runs from drainage holes.
4. Apply a light mineral mulch (gravel, sand, fine slate chippings…) that preserves coolness, limits establishment of competing plants and contributes to decorative effect. Do not use overly heavy or bulky materials (large pebbles) or thick materials (burlap, plastic…)

Ensure thereafter that substrate never dries out completely. Use of a saucer makes, in warm season, a beneficial water reserve. In winter, tip saucer upside down. Choose pots sufficiently large to let Japanese forest grass express freely.

→ Learn more with our advice sheet: Growing 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 the rest, only one annual intervention is necessary, at the end of winter: cut back all dead stems to about 3 to 5 cm above the soil.

Apply a handful of compost to nourish the plant.

For container-grown specimens, proceed in the same way. After a few years, you will need to lift it from its pot and replace the substrate. This operation is also necessary if Hakonechloa has outgrown its pot.

Brilliant foliage display of Hakonechloa ‘Nicolas’ in autumn / Foliage of Hakonechloa ‘Aureola’ still decorative in winter

Multiply

If you wish to propagate it, do so from an established clump and be sure to carry out the operation in spring. Appearance of new shoots signals the right time to start. The only reliable way to propagate your Hakonechloa plants is by clump division.

Stump division

To divide a young plant of Hakonchloa :

1. Cut dried foliage, take a sharp spade, lift out the stump and divide it into several divisions.
2. Replant them immediately and water.
3. In a pot, lift the Hakonechloa out and divide it into several divisions. If you use the same pot, remember to replace the compost 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 pots and in ground. For pot choice, let inspiration guide you. Know that golden leaves of Hakonechloa macra ‘All Gold’ will, for example, contrast wonderfully with deep-blue pot. Ideal planted alone to adorn a patio corner, a terrace or a cool-feeling balcony.Plant in centre of a large pot an Imperata cyclindrica ‘Red Baron’ with upright red leaves surrounded by Hakonechloas. Guaranteed effect!

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

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

Conditions in which Japanese forest grass grows are appreciated by wide range of other plants and there are therefore multiple ways to combine them.

Plant at base of handsome trees or bush with clear trunk to act as setting and also integrate it safely into compositions that suit many styles.

Subtle atmosphere: focus on leaves!

Leaves of Hakonechloa, besides being beautiful, go wonderfully with other shade plants with decorative leaves. Play on shades of green, contrasts of form and texture or compose colourful contrasts. With this approach, border can easily be as attractive as flower border.

Imagine border covered with low tapetum of Helxine of incomparable softness from which one or several clumps of Hakonechloas emerge. In background, plant a Japanese maple, perhaps with purple leaves such as Acer palmatum dissectum ‘Garnet’. A contrast of hues and forms that always remains a safe choice.

Create opulent effect with immense exotic leaves of a Gunnera maticata or a Tetrapanax, or those of a Fatsia japonica ‘Spider’s Web’ for its green splashed with cream-white. If space is more limited, choose a Rodgersia of more modest dimensions.

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

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

Enhance graphic effect with fronds of delicate design from ferns such as Athyrium nipponicum pictum whose leaves throw beautiful metallic sheens, or that of an hosta with bold presence.

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

Let a Pieris complete scene and bring discreet floral note. Forms, sizes, textures and colours of leaves provide long-term spectacle but nothing stops you from adding a few bulbs to mark spring.

Sparkling mood: dare colours!

Japanese forest grass offers leaves that go with wide diversity of perennials or flowering bush. It enhances neighbours, links different colours and acts as pit to create rhythm for most of year.

Many spreading groundcovers thrive on woodland edge or in light understorey. Ajuga brings blue or pink touch between May and June, on leaves you can choose green or purplish. Certain Lamiums offer silvery leaves adorned in spring or summer with white, yellow or pink flowers, very bright in less exposed parts of garden. Epimediums come in wide palette of colours, both for leaves and flowers. Be tempted by Farfugium japonicum with daisy-like yellow flowers in autumn.

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

For bush choice, opt for a Daphne whose scent enchants in midwinter, or a Hydrangea that will bring colour midseason.

Rely on flowering from hellebores, alchemilles, columbines and foxgloves, not forgetting perennial geraniums such as Geranium nodosum, which return faithfully each year.

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

Also consider Hakonechloa in mineral settings. It can either accentuate curves or soften strict lines of stone elements for example.

→ Discover our pairing ideas with Hakonechloa

Did you know?

Poacées are found on every continent worldwide, including the coldest regions such as Antarctica. They grow in a wide range of habitats, from the driest to the wettest, and alone represent an astonishing diversity with more than 12,000 species identified to date. Poacées are among the leading plant families in terms of diversity, behind Orchidaceae, Asteraceae and Fabaceae (formerly legumes).

The word “graminée” is often used to group together a set of plants that look alike but are not all Poacées. This is the case for Carex (Cyperaceae) or woodrush (Juncaceae), for example.

Term “graminée”, which should now be replaced by Poacée, has thus entered common usage. It is still commonly used by many gardeners and nursery growers to refer to plants that therefore do not all belong to family Poacées.