How to Plant, Grow, and Care for Japanese Forest Grass

Ornamental grasses are one of my favorite ways to add texture and movement to the garden. Although many of us look to flowers to add interest and pops of color, a balance of perennials and grasses creates a much lusher landscape that always catches the eye – even when the plants are not in flower.

Finding ornamental grasses for shady areas to plant under trees or pair with your other shade plants can be tough. That is just one of the reasons why the shade-tolerant Japanese forest grass is so popular.

This stunning plant has everything you could ask for in a grass – movement, texture, and variety in color. And as a bonus, it’s also remarkably easy to care for.

What Is It?

This species is scientifically known as Hakonechloa macra, but you’ll also see it called Hakone grass. Like other ornamental grasses, it is a member of the Poaceae family and an incredibly popular one in shady gardens. It is also the only species in this genus, making Hakonechloa monotypic. 

Hakone is a mountainous town in Japan where traveling botanists initially found this species. The specific epithet macra translates to ‘large’ or ‘long’ in Latin, seemingly referring to this lush grass’s arching, strappy leaves.

Although there is only one species within this genus, there are several cultivars to choose from, each with its unique twist. Some have slightly golden or even neon hues, like ‘Aureola’ or ‘All Gold,’ while the variegated cultivars like ‘Alboaurea’ or ‘Naomi’ are particularly popular.

This variety between cultivars gives you plenty of options when planting. Mix it up by pairing a few different colors and sizes, or stick with your favorite for a more uniform look.

Characteristics

This species forms soft mounds of foliage of different sizes, depending on your chosen cultivar. The leaves move subtly in the wind to create a flowing texture that can instantly soften any landscape. They look so inviting you can’t help but run your hand through the leaves as you walk past.

One of the most beloved characteristics of this plant is its ability to grow well in shade. There aren’t many ornamental grasses with a similar look that tolerate shade, ideal for filling gaps under trees or planting beneath taller shrubs. They also look even grander in containers, where the strappy leaves can cascade over the sides.

This grass is a favorite for adding textural contrast to structured gardens. They are often planted at the base of meticulously manicured Buxus to lighten the textures and stop beds from looking too dense and heavy. They are ideal for wilder, prairie-style gardens or softening borders with hard edges.

It is a perfect partner for hostas and ferns in the shade if you like the soft and leafy look. You can also plant them en masse under trees where lawns may struggle to grow, looking particularly stunning in windy areas. They also make a great pairing with hydrangeas, especially during the transition to fall.

Planting

Planting is no more difficult than placing any other ornamental grass. The hardest part is choosing the perfect spot, but after that, the process is straightforward.

Although they can tolerate full sun in moderate climates, choosing a position with partial shade or dappled sunlight is best. These plants perform their best in the garden’s shadier parts, avoiding scorching of the foliage.

Spring is the best time to plant to ensure the roots are established quickly. You can plant in late summer or early fall, but the leaves will likely die back in winter in cold areas, giving you little time to enjoy the plant.

Prepare the soil by digging a hole slightly larger than the current container. If the soil is poor quality, amend it with plenty of compost to give the plants a good start. They prefer soil that stays slightly moist, so sandy soil must be amended before planting.  

Take the plant out of the pot or bag, loosen the roots, and plant. Fill in any gaps with the soil you removed and press around the base to anchor the plant. Water immediately to settle the roots into their new home. You can also add a layer of mulch around the base to retain moisture and keep weeds down.

How to Grow

Despite its delicate look, this grass is not high maintenance. It has slightly different requirements from other ornamental grasses you may be used to, but they won’t trouble you once you plant in the right spot.

Light

This is one of the few ornamental grasses that grows best in partial shade, receiving either morning light and afternoon shade or dappled sun filtered through taller trees. The ideal light should match the natural light of a forest clearing, mimicking their native habitats.

However, this plant tolerates various lighting conditions and can handle full sun if needed. But remember that too much sun can burn the leaves, causing browning edges and an overall sad look. The variegated cultivars are especially sensitive to the sun, scorching quickly if light levels are too high.

It’s best to protect them from direct light – no matter the cultivar – particularly in hot climates where the afternoon sun can become intense.

Similarly, they can tolerate deeper shade, but these conditions negatively impact growth. Rather than a dense mound, the leaves will be thinner and sparser. If you can’t find the ideal spot in your garden, it may be better to plant in containers to make the most of the available conditions.

Water

Maintain consistent moisture to preserve its soft and lush shape. As long as you’ve planted in the right soil and spot, you can typically water them along the rest of your garden with no extra attention. However, if you’ve planted in sandy soil or full sun, you’ll likely need to water more often.

When you do water, it’s best to water the plant deeply, encouraging the roots to grow downward into the soil. Water when the soil just starts to dry out, but watch out for overwatering. The goal is to avoid waterlogging, which can lead to root rot and fungal issues.

Cut back on watering in fall and winter when growth slows down. It’s better to slightly underwater than overwater, as soggy conditions will kill off the root system. Also, adjust your watering routine based on rainfall in your area to maintain ideal soil moisture levels.

A layer of mulch can help retain soil moisture and reduce the need for frequent watering. It also helps keep weeds down while regulating soil temperature – which is especially important in warmer climates.

Soil

Although this grass can adapt to various soil types, it thrives best in rich soil that drains well. If the conditions in your garden don’t quite match up, mix in compost before planting to improve its structure.

Like many perennials, this species prefers slightly acidic to neutral soil. Regular soil testing will help you understand pH levels and any potential nutrient deficiencies to fix.

Temperature and Humidity

This grass grows best in moderate climates, thriving in USDA zones 5 to 9.

It can survive the cold winters in cooler zones but will likely die back over the winter months when temperatures dip too low. Don’t worry – as long as the roots remain intact, you’ll see new green growth popping up again when temperatures rise in spring.

It is not fussy about humidity but appreciates extra moisture in the air during warm summers. If you live in an area with dry summer conditions, consider watering more often during the hottest parts of the year to give them enough moisture.

Fertilizing

When planted in the right soil and mulched regularly, no additional feeding is needed throughout the season.

If the plant is underperforming or you are aware of a nutrient deficiency in the soil, a single application of balanced slow-release fertilizer in spring will boost growth. The plant doesn’t respond well to overfertilizing, developing weak growth, and few leaves, so this annual application is more than enough.

Apply the fertilizer according to the package instructions, ensuring it’s spread evenly around the base of the plant to avoid burning the roots. Water well after fertilizing to help distribute the nutrients into the soil, gently working the fertilizer into the top later.

Maintenance

In early spring, cut back the foliage to a few inches above the ground before new growth kicks in. This will tidy up the plant and allow new leaves to grow. You can also cut back slightly earlier if you want to tidy your garden in winter, but make sure you mulch afterward to protect the roots.

Keep an eye out for dead or discolored leaves and remove them to keep the plant neat and encourage healthy growth. While not prone to many problems with pests or diseases, removing any dying leaves will direct the plant’s energy toward new and healthy growth.

Propagation

If you want to turn a mature clump into two plants to transplant into a new part of the garden, division is the answer. This is also a good practice to complete every three or four years to limit overcrowding, ensuring the grasses always look their best.

Divide clumps in early spring, just as new growth emerges. Start by digging up an established clump, lifting gently from the bottom to limit damage to the root system. Divide the clump into smaller sections with plenty of healthy root growth with a sharp spade or knife.

Replant the divisions into their new homes, whether in the ground or containers, and water well. Maintain consistent moisture for several weeks after planting to help them establish well.

Common Problems

This plant is largely trouble-free. Most issues result from incorrect care or environment, which are easy to prevent.

The first potential problem is leaf scorch, occurring when the plant is exposed to too much direct sunlight or if the soil is allowed to dry out significantly. Planting in a spot out of full sun, especially in a warm climate, is key to avoiding this problem (along with regular watering).

Slugs and snails may occasionally feed on the foliage, especially if tasty hostas are nearby. Regularly check the plant in the early morning or after rain and hand-pick any pests you find.

Root rot is also a concern if you’ve planted them in the wrong soil, overwatered, or have recently experienced sudden heavy rains. Soil maintenance is the first point to fix. Planting in rich soil that does retain some moisture but also drains well. If you notice yellowing leaves or a mushy base, check the roots for signs of rot.

Frequently Asked Questions