Panicum

( PAN - ih - kum )

At-A-Glance Information

Switch Grass needs full sun to light shade and can thrive on any amount of water it is provided. It is native to most of the United States (except for the far western states) and forms a 2-4 foot wide clump of deep green to grey-green leaves. These plants produce open clusters of pink blooms that age to white as they mature and fade. Foliage will yellow in the fall and gradually fade to beige for wintertime. These grasses can tolerate coastal conditions. Most reach about 5 feet tall when in bloom. Use these grasses as vertical accents or screens in beds and borders, in rain gardens or bioswales, for erosion control in sloped areas of the landscape, or simply as wildlife or pollinator plants. Take care when planting these grasses in the landscape, as they are toxic to horses, sheep, and goats if ingested.

panicum Species and Varietals

The genus Panicum includes between 400 and 500 species, and is a member of the plant family Poaceae. Plants in the genus are closely related to those in Pinnesetum (Fountain Grass), Setaria, and Digitaria (Crabgrass). The best growing zones for Moor Grass are USDA hardiness zones 3-9 or Sunset growing zones 1-9 and 14-17. To find your zone, click here: Zone Map.
Panicum virgatum (Switchgrass, Panic Grass, Wobsqua Grass, Blackbent, Tall Prairiegrass, Wild Redtop, Thatchgrass, Virginia Switchgrass, Tall Panic Grass)
This bunchgrass species is native to North America, and reaches up to 8 feet tall, but is typically shorter. Leaves have a prominent midrib and are green in the straight species, turning brown in summertime. Cultivars are listed and described below:
'Cloud Nine'
Metallic blue foliage turns gold in fall, this variety produces billowing clusters of red-brown flowers.
'Dallas Blues'
Powder blue foliage, red-purple flowers. Dependable variety.
'Hanse Herms'
Fountain-like habit, with light green leaves that turn bright red come fall and fade to burgundy.
'Heavy Metal'
Silver-blue foliage that turns bright yellow in fall.
'Northwind'
Vertical plant with olive-green foliage that turns yellow in fall.
'Prairie Sky'
Vigorous grower with an upright habit. Foliage is blue and turns yellow in autumn.
'Rotstrahibusch'
Upright growth to 4 feet tall when in flower. Green foliage is tinted red, and turns deep red in fall. Burgundy flowers.
'Shenandoah' ('Virginia Switchgrass')
​Cascading habit with red-tipped blue-green foliage that turns maroon in fall. Flower clusters are red.
'Squaw'
Leaves are solid green, and turn red in fall. Red flowers.

Caring for Panicum

Install grasses 2-3 feet apart for best coverage and airflow. Plant in full sun; ideally, they like to receive between 6 and 8 hours of direct sun each day for best growth rate and color. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 5.5 and 7.5 (acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these grasses are considered highly drought-tolerant, able to get by on rainwater alone for most of the year. During extended periods of drought, deep water.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. These plants will re-seed freely in the garden; to discourage this, make sure to remove flower spikes before they set and release seed. Volunteer seedlings are easily pulled from areas where they are unwanted, and can be transplanted elsewhere or composted. Once established, a Switchgrass stand can survive for decades before needing to be replaced or re-seeded.

Propagation

Panicum, or Switchgrass, is propagated through division or seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Switchgrass, follow the instructions below:

Propagating Panicum by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, and a spray bottle. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded, and are typically held above the foliage on thin stems. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. Get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Panicum by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in early spring or fall. To propagate by division, follow these steps:
  1. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
  2. Separate the removed patch of grass into sections using a sharp, clean knife or trowel. Ensure that each division has a healthy root system and a few shoots. Any dried out areas with dead roots can be tossed in the compost.
  3. Prepare your pot(s) or new planting site(s) with well-draining soil and compost and work it in. Water thoroughly, and then plant divisions.
  4. Keep soil consistently moist as the newly-planted divisions establish strong root systems in their new home. Provide regular waterings, especially during dry spells.

Problems and Pests

Panicum grasses can be susceptible to developing issues with the following pests and diseases in the landscape:
  • Japanese Beetles
  • Thrips
  • Spider Mites
  • Rust 
  • Leaf Spot
  • Root Rot
For more information on these issues, including how to treat and prevent them, consult the following pages:
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Gallery

Panicum grasses can be used in mixed beds to add movement and texture.
This drought-tolerant bed features Panicum virgatum.
The variegated foliage of Switchgrass can illuminate darker areas of the garden.

Videos

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Resources

How to Grow and Care for Switchgrass
Have You Switched to Switchgrass?
Wikipedia: Panicum
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 472, Panicum virgatum (Switch Grass)