How to Plant and Grow Switchgrass

Switchgrass, a tough ornamental grass that stands up to a variety of harsh conditions, adds both texture and color to a garden. It spreads slowly over time and adds stunning vertical accents wherever it is planted. This warm-season grass blooms in mid to late summer. Some varieties and cultivars have foliage that changes color in the fall.

Switchgrass has come a long way from being the plain grass that dominated the native tall-grass prairies of North America. Many of the recent introductions bring longer displays of colors with varieties in glowing red and burgundy. When flowering, some switchgrass varieties boast a soft pink cast on their blossoms, making them an option to contrast the blue varieties. Come fall, the show intensifies, and many of the red-tinged varieties turn a rich burgundy color while others take on a golden hue. In the winter, the dried flower heads bring texture to the garden, especially when dusted with snow.

Where to Plant Switchgrass

Ideally, plant switchgrass in full sun and moderate-to-moist sandy soil, but if these aren't available, this drought-tolerant plant adjusts to other soil conditions. It is a popular choice for prairie restoration and the Conservation Reserve Program (CRP), but it is equally at home in the garden at the back of a mixed-border, as a screening plant, or in a pollinator garden, where it attracts bees, moths, butterflies, and birds.

How and When to Plant Switchgrass

Switchgrass is available in nursery containers and can be planted any time the ground isn't frozen. The only preparation most soils need is to be thoroughly cultivated to accommodate the long taproot. Dig a hole the same size as the rootball, set the plant at the same level it grew in the nursery container, and water it well. When planting more than one switchgrass plant, space them at least 12 inches apart, and keep them at a distance from smaller plants they might overwhelm. It is quick to grow but slow to establish, and it reseeds prolifically. A heavy mulch will reduce volunteer seedlings.

Seed may be a better choice than nursery plants when planting a large stand of switchgrass. If using cold stratified seed, sow the seed in the spring after the soil temperature reaches 60°F. If the seed hasn't been stratified, plant it in late winter. When the weather warms, soak the seeds in water overnight before planting them. Poke a 1/2-inch deep hole in the soil for each seed and drop a seed in each hole, spacing them 2-4 inches apart. Cover the seeds with a little soil but don't pack it down. Water the planting area and continue to water occasionally until the seeds germinate. When the seedlings are 4 inches tall, thin them to the desired spacing.

Switchgrass Care Tips

Switchgrass is a relatively low-maintenance plant that requires little care to thrive.

Light

For the most vibrant colors, plant switchgrass in full sun. This prevents them from falling over, as many varieties can grow 6 feet or more. In shade, many of these varieties, especially older ones, fall if not supported. Full sun also provides the best blossoms.

Soil and Water

Switchgrass thrives in sandy soil with a fair amount of organic matter. For the best results, keep it evenly moist and avoid planting in soggy, heavy clay soil. Once established, switchgrass can handle droughts. Some species and cultivars even tolerate salt spray.

Temperature and Humidity

Switchgrass is a perennial warm-weather plant. It goes dormant during the winter to survive the cold temperatures. During the growing season, it thrives in a temperature range of 60°F to 95°F and prefers low-to-average humidity.

Fertilizer

Don't worry about fertilizing. Switchgrass has an extensive root system that goes deep into the soil to get needed nutrients. Excessive fertilization results in floppy plants.

Pruning

Leave switchgrass uncut going into the winter to provide cover, cold protection, and seeds for wildlife. Then, in late winter or early spring, before new growth emerges, cut back the old foliage to a few inches above the ground. Because of their dense, slowly spreading habit, these plants make solid clumps of foliage that can choke out weeds. As they get older, the centers of these plants may begin to die out. If this happens, dig up the plant and divide it to re-energize and continue its growth.

Potting and Repotting Switchgrass

Young switchgrass can be grown in a container for only about a year while its root system develops. The plant has an extremely long tap root that eventually grows as long as 10 feet. It isn't a good candidate for extended container life. After a year, it can be transplanted to the garden.

Pests and Problems

Switchgrass is pest-resistant, but it is possible it will attract aphids, leafhoppers, beetles, or grasshoppers. Several organic methods exist to control these unwelcome visitors.

When crowded or grown in too-soggy soil, the plants can encounter crown rot or root rot.

How to Propagate Switchgrass

The easiest way to propagate switchgrass is through division. The plants benefit from being divided every three years anyway. Wait until the soil warms in spring to divide the plant; the roots need warm soil to develop. Use a sharp knife to cut off a section from the outside of the clump that contains both stem and roots, or dig up the entire plant and use a sharp spade to cut the clump into quarters. Immediately replant the sections into pots filled with potting soil or directly in the garden.

Switchgrass is a prolific reseeder. You may just need to look around the plant to find a collection of new plants ready to be transplanted. However, you can harvest switchgrass seeds by cutting a seed head and stem after the bloom is spent but before the seed disburses. Put the stem and head into a paper bag and place it in a warm place to dry. The seeds will need to be cold stratified, either by planting them outside in the winter for the following season or by putting them in a plastic bag in a refrigerator for a month before planting them in a prepared garden bed in spring.

Types of Switchgrass

'Cloud Nine' Switchgrass

Panicum virgatum 'Cloud Nine' has clumps of metallic-blue foliage topped with clouds of spikelets that turn reddish-brown in fall. This variety may reach 6 feet tall. Zones 5-9.

'Heavy Metal' Switchgrass

Panicum virgatum 'Heavy Metal' is a favorite variety prized for its lustrous steely blue foliage and golden fall color. These plants form impressive upright columns up to 5 feet tall in bloom. Zones 4-9.

'Shenandoah' Switchgrass

Panicum virgatum 'Shenandoah' is one of the reddest switchgrasses. Its strong color shows itself by early to midsummer and becomes more intense as the season progresses. It reaches 3 feet tall. Zones 5-9.

'Northwind' Switchgrass

Panicum virgatum 'Northwind' was a Perennial Plant of the Year in 2014. This grass has lovely blue-grey foliage and is extremely drought tolerant, with narrow, graceful blooms reaching upward of 5 1/2 feet tall. Zones 4-9.

Switchgrass Companion Plants

Black-Eyed Susan

Add a pool of sunshine to the garden with a mass planting of black-eyed Susan. From midsummer, these tough native plants bloom their golden heads off in sun or light shade and mix well with other perennials, annuals, and shrubs. Tall varieties look especially appropriate among shrubs, which in turn provide support. Add black-eyed Susans to wildflower meadows or native plant gardens for a naturalized look. Average soil is sufficient for black-eyed Susans, but it should be able to hold moisture fairly well.

Aster

Asters get their name from the Latin word for "star," and their flowers are indeed the superstars of the fall garden. Some types of this native plant can reach up to 6 feet with flowers in white and pink but also, perhaps most strikingly, in rich purples and showy lavenders. Not all asters are fall bloomers. Extend the season by growing some of the summer bloomers, as well. Some are naturally compact; tall types that grow more than 2 feet tall benefit from staking or an early-season pinching or cutting back by about one-third in July to keep the plant more compact.

Crocosmia

No late summer flower garden is complete without crocosmia's vibrant wands of scarlet, red, orange, and yellow. They offer a late pop of color when many gardens are languishing in the dog days. Their narrow, bladed foliage provides vertical accents, much like gladiola leaves. The tubular blossoms beckon hummingbirds, and the seedpods that persist into fall also attract feathered visitors. Plant crocosmia bulbs in well-drained soil in fall or spring.

Garden Plans for Switchgrass

Easy-Care Summer-Blooming Shade Garden Plan

This mix of flowering shrubs and perennials will fill your yard with color all summer long—plus provide interest in spring, fall, and winter.

Easy Streetside Garden Plan

Turn a streetside strip into a heavenly oasis of color and bloom with fuss-free native plants.