June 2003
Plant of the Month
Fiber Optic Grass
(Scirpus cernuus)
zone: 4
by Neil Anderson

Fiber Optic Grass creating “sedgesational” interest

Now that spring fever has infected us, plants are flying off the shelves at retail garden centers for early planting. In my travels to local retail hotspots, visits with home gardeners and landscapers, I’m always discussing the hottest new herbaceous annuals or perennials. Once again, fiber optic grass has caught my eye; it’s surfacing everywhere—from Linder’s to Tangletown Gardens—creating intriguing displays and containers. I knew this was a sensation when one of the custodians in my building asked me where she could find it! Customers are asking for it by name.

Fiber Optic Grass, known as Scirpus cernuus (=Isolepis cernua), is a member of the sedge family (Cyperaceae). Other common names include Bulrush and Club Grass. The genus Scirpus also includes freshwater, giant bulrushes. S. cernuus is a dwarf plant (12” maximal height) that grows in a dense habit with wire-like, translucent stems tipped with green buds in the spring and creamy-white flower clusters in summer that turn rusty brown as they age (Suncrest Nurseries, 2003). In its native habitats it can be found growing in full sun moist to wet, muddy-silty to saline intertidal mudflats. Plant these approximately 10”-12” apart.

Unlike the popular and non-hardy Carex buchananii, which one can never tell whether its alive or not due to its brown foliage, Fiber Optic Grass plant looks like a dwarf ‘Cousin It’—with fine, lush green hair tousling in the wind. The fiber optic appearance makes it an unusual addition to water gardens, ponds, border plantings, beds, and containers (Proven Winners, 2002). Weak stems allow the plant to lazily hang over the edges of containers. It prefers full sun to light shade and constant moisture, growing favorably in most soils.
Fiber Optic Grass is usually a vegetatively-propagated item (divisions), although seed propagation may be invoked (stratification is necessary). This Scirpus is a non-hardy annual; its tolerance of cool temperatures suggest it to be hardy from 20°F to 0°F. Fiber Optic Grass may be brought inside during the winter as a houseplant, provided adequate light and moisture are available, although it is unclear how long it will survive in these conditions. Many local retailers carry Fiber Optic Grass, purchasing liners or finished material from the John Greenlee Collection® (Proven Winners) or Suncrest Nurseries. Some of the tags being used have incorrect spellings of the scientific names.
There are other ornamental sedges that can be used to complement Fiber Optic Grass that are taller and may be used to create “sedgesational” interest in your plantings this year.
Scirpus lacustris var. tabernaemontani 'Zebrinus', known as Zebra Rush, forms bunches of nearly leafless stems that are banded horizontally with white. Zebra Rush, growing to 5’ in height, has minute brownish-red flowers arranged in a spikelet.
Scirpus cyperinus, Woolgrass Bulrush, is shorter than Zebra Grass, growing 3-5’ high with an umbel of spikelets at the tip of its slender stems. When the fruit are ripe, the spikelets have a woolly appearance.

Proven Winners. 2002. Plant care for the home gardener: Fiber Optic Grass, Scirpus cernuus. www.provenwinners.com
Suncrest Nurseries. 2003. Scirpus cernuus, Fiber Optic Grass. www.suncrestnurseries.com/specialistdescrpt/scirpuspb.html

By Neil Anderson, Floriculture Professor & Flower Breeder, University of Minnesota.

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