How to Grow and Care for Switchgrass

Switchgrass is a tall, native North American, warm-season perennial. This prairie grass has small, teardrop-shaped flower seeds that appear in the summer with purplish-reddish tips. It turns to shades of yellow in the fall and lightens further in the winter. It remains upright unless under heavy snow. Switchgrass is an easy-to-grow ornamental grass, growing best in full sun and moist soil but is drought tolerant, adjusting to various temperatures and soil conditions. It grows fast from seed and division in warm soil but slowly matures, usually taking about three years.

Benefits of Switchgrass

This low-maintenance plant is resistant to disease and not bothered by pests. With its spreading rhizomatous roots and clump-forming habit, switchgrass is ideal for use in sloped areas prone to erosion.

Switchgrass is also grown for hay and cattle feed, feeding deer, and providing cover for prairie animals.

It is being heralded as the next leading biofuel crop in the United States. Fuel made from switchgrass seems more efficient than corn. Switchgrass contains more than five times as much energy than it takes to grow and refine it into ethanol—although the refinement process has not been established yet.

Switchgrass Care

Here are the main cultural considerations for growing switchgrass.

• Grows in many regions of North America, from the southern United States and Mexico to areas as far north as Canada.
• Begins new growth in late spring and provides visual interest throughout the year.
• Spreads rapidly by rhizomes.
• Prefers full sun but can grow in partial shade.
• Thrives in moist sand or clay, although it handles many soil types well and is drought resistant.
• Tolerates intense heat and freezing cold.
• Droops if in highly enriched soil.

Light

Switchgrass prefers a full sun position. This will ensure vigorous growth, tall and upright stalks, and the most interesting color. It can handle part shade but be prepared for the stalks to droop and the clumps to be less tightly formed. 

Soil

Part of the appeal of switchgrass is that it can tolerate being planted in most soil types. It does, however, prefer a moist sandy or clay variety. Be aware that if the soil is overly rich, this could result in the stalks flopping, and you may need to stake them up.

Water

A drought-tolerant species, switchgrass can handle dry and hot conditions well. For best growth, though, it prefers to be kept moist. It can even handle light flooding; sometimes it's used successfully in boggy areas around ponds.

Temperature and Humidity

Tolerant of a wide range of weather conditions, this grass variety can cope with intense summer heat and freezing winter conditions.

Fertilizer

Once established, rhizomatous switchgrass rarely needs additional feeding with a fertilizer. Too many nutrients can cause the grass stalks to droop.

Types of Switchgrass

There are a wide variety of switchgrass cultivars. Some ornamental cultivars can be more sensitive to their environments than others, so checking their needs before planting is essential. Some of the most popular or unique include:

• 'Blue Tower': Very tall cultivar with distinct bluey-green foliage that can grow to reach 8 feet in height
• 'Dallas Blues': Wider, blue leaves than other switchgrass varieties; forms in very dense clumps; particularly drought-tolerant; produces copper color in the fall
• 'Shenandoah': One of the smallest switchgrass cultivars; only reaching around 2 to 3 feet in height
• 'Cloud Nine': Dark blue leaves turn to gold during the fall
• 'Prairie Fire': 5-foot leaves turn deep red in summer and yellow in the fall

Pruning

Cut the foliage to a few inches above the ground in late winter or early spring (after the first growing season) to encourage healthy new growth.

Propagating Switchgrass

Although switchgrass can grow quickly from seeds harvested from your mature grass, seedlings may differ significantly from the original plants. To replicate the shades and height of the plants you already have in your garden, divide the clumps instead.

Division is best done in the late spring as the roots need warm soil to establish. Clump division is recommended every few years, as the center of the clumps begin to die out, which will help boost their vigor.

Here's how to divide switchgrass:

• Depending on the clump size you want to grow, you'll need a sharp knife or a shovel. You may also need a pot with fresh potting soil.
• If you want to grow a small cluster, carefully dig out a stem with its roots intact from the outside of a clump using a knife. Transplantation from a clump into a pot kept indoors can be done any time of the year.
• Plant it in a pot, let it grow for a year, and transplant it outdoors in a full-sun location.
• To grow a larger clump, dig up the entire clump using a shovel. Dig down with your shovel, in a circle, around the clump to uproot the whole clump.
• Divide the clump in fourths using the shovel end and replant it in a favorable location. This should only be done in the spring since this is an intrusive method that can stress the plant. Springtime is a time of active growth, and recovery is most likely.
  

How to Grow Switchgrass From Seed

Seeds need plenty of light, moisture, and warm conditions to germinate. Seedlings form quickly—usually within a few weeks. They take hold easily, so start them indoors in typical potting soil and give them ample light from a sunny windowsill. Regular watering is enough to give them a good start. However, this plant takes time for its rhizomes to establish.

1. Sow seeds in the spring after the soil temperature reaches 55 F.
2. Make sure it's in a full sun location and moisten the ground.
3. Plant on a firm, well-prepared seedbed at 1/2- to 3/4-inch depth.
4. Keep the soil moist to encourage vigorous growth.

Potting and Repotting Switchgrass

Switchgrass can be started in a pot or grown in a container for about a year as its rooting structures develop and establish. It has a long taproot that will grow 10 feet long or more. It is not the best plant for continued growth in a pot, although mature specimens can be grown in large, heavy, deep pots. When potting, you must also give the grass more water than ground planted specimens.

It can be transplanted successfully from a pot without too much stress outdoors in the spring when the soil temperature has warmed to at least 55 F.

Overwintering

No special care is needed for overwintering switchgrass. It is cold-hardy to USDA zone 3, which includes places like northern Minnesota, Wisconsin, North Dakota, and Maine. It can withstand temperatures as low as -40 to -30 F. It grows year after year, returning in the spring when soil temperatures warm up.

Common Pests and Plant Diseases

Switchgrass is strongly resistant to pests; the ones that do affect the grass from time to time, such as aphids, don't often cause serious damage.

Fungal diseases, however, are much more common. These might include rust, leaf spot, and smut. A fungicide can be beneficial in keeping large-scale problems with fungal diseases at bay.

Common Problems With Switchgrass

Switchgrass is a potential vector for the Japanese beetle and Spotted wing drosophila, which can wreak havoc on commercial crops, especially fruits. Switchgrass planted near large farms can be a potential problem, so keep the location of your garden and landscape design in mind when you plant switchgrass.

Not Growing or Emerging

Switchgrass is a warm-season grass that thrives in the heat of summer and goes dormant in the cold winters. The soil must be at least 55 degrees Fahrenheit or warmer to germinate or grow.

Yellowing Leaves

Frequent, heavy rain or overwatering can lead to yellowing. If you see the grass turning yellow, cut back on watering. Another potential cause of yellowing is nutritional imbalances. Check your pH levels; also, the fertilizer salts might be off-kilter. Yellowing can often turn around with a liquid feed of fertilizer 10-10-20 that contains iron.

Floppy Grass

If your switchgrass was growing well but then starts to get floppy or fall flat, ensure it has full sun. It tends to get floppy in a shady location or if it gets too much fertilizer.