Switch Grass
Panicum virgatum

Family: Poaceae

What it is like

Panicum virgatum is a PERENNIAL growing to 1.8 m (6ft) by 0.3 m (1ft in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 10. The flowers are pollinated by Wind. It is noted for attracting wildlife. Suitable for: light (sandy) and medium (loamy) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought. The plant can tolerate maritime exposure.

Height (m): 1.8

Where it is found

Found in both wet and dry soils in prairies and open woods, gravel bars and stream banks and along railroad tracks.

Found in many areas of the world, especially in the temperate and subtropical zones, but also in the tropics, especially in the Americas.

Conservation Status: This taxon has not yet been assessed

Countries/locations it is found in

Asia, Canada, Central America, China, Mexico, North America*, USA

How it is used

Food

Rating: 0

Medicine

Rating: 0

Other

Rating: 2

Agroforestry Uses: A valuable soil-stabilization plant, it is used as ground cover to control erosion. It can be used as an energy substitute and is often considered a good candidate for bio-fuel, especially ethanol fuel production, due to its hardiness against poor soil and climate conditions, rapid growth and low fertilization and herbicide requirements. The plant is sometimes used as a windbreak in crop fields. Switchgrass is an excellent forage for cattle; however, it has shown toxicity in horses, sheep, and goats

Industrial Crop: Biomass: Three broad categories: bamboos, resprouting woody plants, and giant grasses. uses include: protein, materials (paper, building materials, fibers, biochar etc.), chemicals (biobased chemicals), energy - biofuels

Management: Hay: Cut to the ground and harvested annually. Non-destructive management systems maintaining the soil organic carbon.

Regional Crop: These crops have been domesticated and cultivated regionally but have not been adopted elsewhere and are typically not traded globally, Examples in this broad category include perennial cottons and many nuts and staple fruits.

Industrial Crop: Biomass: Three broad categories: bamboos, resprouting woody plants, and giant grasses. uses include: protein, materials (paper, building materials, fibers, biochar etc.), chemicals (biobased chemicals), energy - biofuels

Management: Hay: Cut to the ground and harvested annually. Non-destructive management systems maintaining the soil organic carbon.

Regional Crop: These crops have been domesticated and cultivated regionally but have not been adopted elsewhere and are typically not traded globally, Examples in this broad category include perennial cottons and many nuts and staple fruits.

Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.

How it is grown

A plant of the temperate zone, it has spread into the subtropics and tropics. It grows best in areas where annual daytime temperatures are within the range 17 - 32°c, but can tolerate 6 - 36°c. It can be killed by temperatures of -10°c or lower, though new growth can be damaged at -1°c. It prefers a mean annual rainfall in the range 500 - 1,100mm, but tolerates 350 - 2,700mm. Grows in any moderately fertile, well-drained soil in a sunny position. A drought resistant plant, it is easily grown in average to wet soils and in full sun to part shade. Prefers a pH in the range 6 - 7, tolerating 4.9 - 8.2. The plant has a high risk of becoming a weed in any new area into which it is introduced. Plants have particularly heavy growth in late spring and early summer. The plant has the potential to produce the biomass required for production of up to 380 litres of ethanol per metric ton. This gives it the potential to produce over 400 litres of ethanol per hectare, compared to 270 for sugarcane and 160 for corn. However, there is debate on the viability of switchgrass, and other bio-fuels, as an efficient energy source. University of California, Berkeley professor Tad Patzek argues that switchgrass has a negative ethanol fuel energy balance, requiring 45% more fossil energy than the fuel produced. The plant photosynthesize by a more efficient method than most plants. Called the 'C4 carbon-fixation pathway', this process is particularly efficient at high temperatures, in bright sunlight and under dry conditions. As an open pollinated species, switchgrass expresses tremendous genetic diversity, with wide variations in its basic chromosome number (2n = 18), typically ranging from tetraploid to octoploid. Morphologically switchgrass in its southern range can grow to more than 3 m in height, but what is most distinctive is the deep, vigorous root system, which may extend to depths of more than 3.5 m.. It reproduces both by seeds and vegetatively and, with its perennial life form, a stand can last indefinitely once established. Standing biomass in root systems may exceed that found aboveground, giving perennial grasses such as switchgrass, an advantage in water and nutrient acquisition even under stressful growing conditions.

Propagating it: Seed - sow in a nursery seedbed in a sunny position, only just cover the seed and make sure the compost does not become dry. Germination should take place within a week. Prick out the seedlings into individual pots and plant them out when large enough. Division as the plant comes in to new growth. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade until they are well established before planting them out.

Best place to grow:

Habit: Perennial

Hardiness: 10-12

Growth: Fast

Soil: Light (sandy), medium

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

The plant has a high risk of becoming a weed in any new area into which it is introduced.

Its other names

Local names

Common names for switchgrass include tall panic grass, Wobsqua grass, blackbent, tall prairiegrass, wild redtop, thatchgrass, and Virginia switchgrass.

Synonyms

Chasea virgata (L.) Nieuwl. Eatonia purpurascens Raf. Ichnanthus glaber Link ex Steud. Milium virgatum (L.) Lunell Panicum buchingeri E. Fourn. Panicum coloratum Kunth Panicum coloratum Walter? Hitchcock Panicum giganteum Scheele Panicum glaberrimum Steud. Panicum havardii Vasey Panicum ichnanthoides E. Fourn. Panicum kunthii E. Fourn Panicum pruinosum Bernh. ex Trin. Panicum purinisum Bernh. ex Trin.