Switchgrass (Panicum virgatum) is a tall prairie grass that, alongside being grown as food for cattle, is commonly used ornamentally in garden spaces.
A warm-season grass, you won't see growth until the late spring, but it provides interest through most of the year. The small, teardrop-shaped flower seeds that appear in the summer have a pinky/purply tinge, and the green foliage can feature shades of red. It also turns to shades of yellow in the fall. The stalks and plumes lighten further in the winter and tend to remain upright unless there's heavy rain or snow.
With it's spreading rhizomatous roots and clump-forming habit, it's ideal for use on sloped areas prone to erosion. Its also used for adding height and contrasting interest in perennial borders, as a seasonal screen, or for growing en-masse in wild meadow gardens or around the edges of ponds. The flower stalks are also popular for use in dried flower arrangements.
This adaptable and hardy grass can handle drought, boggy conditions, and a wide variety of soil types. Some ornamental cultivars, however, can be more sensitive to their environments than others, so it's important to double-check before planting.
|Botanical Name||Panicum virgatum|
|Common Name||Switchgrass, Tall Panic Grass|
|Plant Type||Perennial, Buncgrass|
|Mature Size||Up to 6 ft. tall|
|Sun Exposure||Full Sun, Partial Shade|
|Soil Type||Sandy, Clay, Moist|
|Soil pH||Acid, Neutral, Alkaline|
|Hardiness Zones||3 - 9, USA|
|Native Area||North America|
Although switchgrass benefits from plenty of sun, it can adapt to a wide range of temperatures and soil conditions and is very low-maintenance. It's also resistant to disease and not bothered by pests.
Not as prolific as some ornamental grass varieties, if the conditions are optimal, it can still spread rapidly. Care should be taken when using it in small garden spaces.
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, too, but be prepared for the stalks drooping and the clumps being less tightly formed.
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 if overly rich, this could result in the stalks flopping and you may need to stake them up.
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, and this is why it's also sometimes used 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.
Once established, rhizomatous switchgrass rarely needs additional feeding with a fertilizer. In fact, too many nutrients can cause the grass stalks to droop.
There are a wide variety of switchgrass cultivars. Some of the most popular or unique include:
- ‘Blue Tower’ – a very tall cultivar, with distinct bluey-green foliage, that can grow to reach 8 feet in height.
- ‘Dallas Blues’ – with wider leaves than most switchgrass varieties it forms in very dense clumps. It's also known for being particularly drought-tolerant.
- 'Shenandoah' - this is one of the smallest switchgrass cultivars, and it only reaches around two to three feet in height.
Switchgrass can easily be propagated through the division of clumps. It's best to do this in the spring as they need warm soil to establish.
Division is recommended every few years anyway, as the center of the clumps can begin to die out, and this will help to boost their vigor.
Cutting back the foliage heavily in late winter or early spring is recommended for encouraging healthy new growth.
How to Grow Switchgrass From Seed
Although switchgrass can grow easily from seeds, it's worth noting that the seedlings often differ significantly from the original plants. If you want to replicate the shades and height of the plants you already have in your garden, it would be better to divide the clumps instead.
Seeds need plenty of light, moisture, and warm conditions to germinate. Seedlings form quickly—usually within a few weeks.