How to Plant, Grow, and Care for Fiber Optic Grass – Full Guide

By: Melissa Pino Published: 13 Jun, 24

Fiber optic grass is a unique ornamental plant that’s perfect for anyone looking to add texture and charm to their garden.

This plant’s eye-catching, cascading green strands make it one of my favorite plants for creating lively accents in various settings, from garden beds to water features.

If you want to grow fiber optic grass, it’s easy to care for. I’ve written this brief guide to help other gardeners cultivate this grass.

Fiber Optic Grass: Finer Details

Fiber optic grass against a white wall

Scientific Name: Isolepis cernua
Other Common Names: Live Wire Grass, Livewire, Fairy Lights, Bulrush
Height When Fully Grown: 10-14 inches
Native Areas: Western and Southern Europe, North Africa, West Coast of North America (California to British Columbia and Alaska), Australia, the British Isles, and New Zealand
Family: Sedge Family (Cyperaceae)
Plant Type: Annual, Perennial
Hardiness Zone: 8-11
Typical Colors: Bright Green, with White to Silver Flowers

Fiber optic grass isn’t actually a grass, but rather, a member of the sedge family, Cyperaceae.

I suggest knowing the difference between sedges and grasses because grasses handle drier conditions, while sedges, like fiber optic grass, need wet conditions to thrive.

Originating from diverse regions, I adore the look of this unique plant. It’s captivating thanks to its lush green, hair-like foliage, which ends in small, fluffy flowers—mimicking the look of fiber optic cables.

Many gardeners find this plant fascinating for its growth habits and distinctive, mop-like appearance and elegant, drooping foliage.

Fiber optic grass thrives in wet places, including sandy or peaty areas near the sea. This plant will grow rapidly in spring, but typically dies during the winter.

It’ll bring a touch of whimsy to your water garden with the charming “fiber optics” on its stem tips, and wonderfully complements other plants.

Maintaining Healthy Fiber Optic Grass

I’ve used fiber optic grass to add a soft texture to containers, garden borders, and miniature gardens. It can also complement an indoor area when placed by a sunny window.

This is a relatively low-maintenance plant, but understanding its basic needs is key to keeping it healthy. Here are my tips for keeping your plant healthy.

Proper Sunlight Levels

Fiber optic grass prefers full sun to partial shade. It thrives in bright conditions, and full sun ensures the best growth and color.

I recommend placing the pot in a window with full or partial sun access.

It can tolerate some shade, although I’ve found this might lead to a looser growth habit. For optimal growth, ensure the plant receives at least six hours of sunlight daily.

The plant will still be healthy in partial shade, but might not be as compact or vibrant.

How Often to Water Fiber Optic Grass

Here are my tips for maintaining healthy fiber optic grass, whether planted in the ground or in containers.

If you move it to a wet or boggy area, ease it in. Keep the plant potted for a few weeks, gradually increase watering, then slowly introduce it to its new area.
Consistent soil moisture is vital, so keep the soil damp but not soggy.
Water your grass daily during hot and dry periods and use pots with drainage holes to avoid waterlogging, especially for container-bound plants.

Soil Preference

In my experience, this grass-like plant prefers wet soil with a slightly acidic pH of 5.8 to 6.2. It’s perfect for water gardens or the water’s edge as it tolerates standing water.

Keep the crown slightly above the waterline if you have a water garden. The roots can handle being submerged, but this grass-like plant prefers its roots damp, not completely underwater.

When growing plants in a container, water them more frequently. Fiber optic grass turns brown if it dries out.

If your plant turns brown, it can be removed immediately or left until spring.

Keeping Fiber Optic Grass Safe During Winter

Fiber optic grass is a perennial in warmer climates like USDA zones 8 and above, returning each year. However, in colder areas where winter temperatures exceed 20 degrees, I’d suggest treating it as an annual.

To overwinter your plants in colder climates, bring them indoors before the first frost when temperatures drop.

Fiber optic grass won’t survive freezing temperatures, so ensure the foliage remains healthy by maintaining a warm environment and adequate moisture.

Propagating Fiber Optic Grass

You can propagate fiber-optic grass from seed or by division to enhance your garden’s beauty, revitalize mature plants, and stimulate new growth.

Seeds

Start seeds indoors in early spring, as they’ll need sufficient amounts of sun to germinate. I’ve found germination typically takes 14-21 days.

Use small pots with damp potting mix and press the seeds lightly into the container.

Keep its container on a bright windowsill or in a warm room while maintaining even soil moisture.

Division

Growing fiber optic grass from seeds is easier, and it will self-seed under the right conditions, but I find dividing the plant when it outgrows its container faster.

Division is best done in spring.

Lift the plant and divide it into sections with healthy roots and foliage. Replant each section at the same depth in the garden or separate pots and water well.

Other Guides from Planet Natural:

How to Plant, Grow, and Care for Switchgrass – Complete Guide

The Basics of Growing Cord Grass – Everything You Need to Know

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Melissa Pino

Melissa Pino is a biologist, master gardener, and regular contributor for Planet Natural. Melissa's work focuses on promoting environmentally-friendly practices, helping people create healthy gardens and finding ways to achieve overall health and wellness.