Growing from tough fibrous roots, prairie dropseed has fine-textured, hair-like leaves that create an arching mound from which flower stalks containing panicles of pinkish-brown flowers rise 30 to 36 inches tall in summer. The foliage turns golden-orange in fall, then fades to bronze in winter. The clumps are not easily flattened by snow, allowing prairie dropseed to remain quite attractive in winter. The common name “dropseed” derives from the tiny mature seeds falling from their hulls in fall. Prairie dropseed is usually planted from plugs or root divisions in the spring, as it is a slow-growing plant that can take as long as four years to reach flowering maturity if planted from seeds. Once established, prairie dropseed is quite long-lived for an ornamental grass.
Light
The grass does best in full sun. Locations with six or more hours of direct sunlight are ideal, but it can also grow in partial shade. Expect reduced flowering in shady conditions.
Soil
As long as it is well-drained, prairie dropseed tolerates a wide range of soils, even clay soil. What it prefers, however, are dry, rocky soils that resemble its native Great Plains habitat. It tolerates a wide range of soil pH, though the soil in its natural habit tends to be somewhat alkaline.
Water
Prairie dropseed has good drought tolerance. In areas with regular rainfall during the growing season, watering is usually not necessary. In areas with extended drought periods during the summer, water it weekly, or more often in intense heat. However, avoid overwatering, which will actually harm it.
Temperature and Humidity
The grass is well adapted to a wide range of temperatures, both hot summers and subzero winters. Humidity does not affect prairie dropseed.
Fertilizer
The grass thrives in poor soils and fertilizer is usually not required.
Types of Prairie Dropseed
Prairie dropseed is widely available in nurseries in its species form.
Sporobolus heterolepis ‘Tara’, a cultivar, is a vase-shaped, compact variety that grows only 18 to 24 inches tall. It is more upright and uniform than the straight species.‘Morning Mist’, another cultivar, has upright reddish flower stems and grows to about 2 feet tall. It is known to remain upright rather than drooping as the seeds ripen.
Pruning
No pruning is necessary for this plant during the growing season. However, it pays to cut it back during the late winter or early spring to make way for new growth.
Propagating Prairie Dropseed
While the name suggests that prairie dropseed scatters its seeds around and reseeds itself freely, that is not the case. The seeds do drop to the ground, yet germination is slow and finicky, and a seedling can take four to five years to reach maturity. Prairie dropseed propagates on its own rapidly through the root system, and propagation is normally done by dividing this tough, fibrous roots system. This is not an easy job, however, as the root system is very dense, which can make it difficult to divide the grass: This division should be repeated every few years, or whenever the center crown grows too dense to be productive.
How to Grow Prairie Dropseed From Seed
Though prairie dropseed takes a long time to germinate and grow from seed in the wild, it is much easier to grow from seed when starting indoors. Keep the seeds in cold storage, such as a refrigerator, for several weeks for cold stratification before planting. Sow the seeds indoors about four weeks before you expect outdoor nighttime temperatures to be reliably at 50 degrees Fahrenheit or more. Sow the seeds in seed-starter mix and keep them at about 70 degrees Fahrenheit, the perfect temperature for germination. Grow lights may help speed germination, and keep the soil consistently moist until the seedlings are well developed. When the seedlings are about 3 inches tall, they are ready to be planted outside. Keep ample spacing between them, as the roots will spread. But don’t expect plants started from seed to flower for several years.
Potting and Repotting Prairie Dropseed
Perennial grasses such as prairie dropseed are not common choices for container culture, though it is certainly possible to grow them in pots for use on patios or decks. Use a large, well-draining container filled with standard potting mix blended with sand or pumice to improve its drainage. Because these plants prefer slightly alkaline conditions, a handful of agricultural lime blended in can be helpful for countering the slight acidity of peat-based potting mixes. Potted grasses should be moved to a sheltered location out of the wind during the cold winter months. Repotting is necessary only when the root crown begins to die out in the center, at which point it should be divided with individual pieces repotted in separate containers.
Overwintering
Like most other grasses, prairie dropseed will turn brown and wither in the winter, but come back hearty in the spring with no intervention on your part. Late winter or early spring is the best time to pull or cut back the dead stalks in anticipation of new spring growth.
Common Pests and Plant Diseases
Part of the appeal of prairie dropseed is that it is not affected by any serious pests or diseases. It is also deer-resistant.
How to Get Prairie Dropseed to Bloom
This native grass will normally flower amply with pinkish-brown panicles in mid to late summer, provided it is getting plenty of direct sunlight. Shady conditions will cause reduced flowering. Overly rich soils or excessive fertilizer may actually reduce flowering, as this plant prefers rather poor, dry soils.
Common Problems With Prairie Dropseed
This plant has very few cultural problems, as it is better behaved and less prone to rampant spreading than other ornamental grasses. But as a clump gets old, it may develop bare spots in the center of the grown as the root ball becomes too dense and fibrous. At this point, it’s time to dig up and divide the clump, discarding the overgrown center crown. Ornamental grasses should be used carefully in regions prone to wildfire. While the dried grass clumps are attractive, they will very easily catch fire if drifting embers fall on them. This slow grower stands out for the fragrance of its flowers, which is very unusual for a grass. While the flowers might look rather inconspicuous, their smell is similar to that of coriander, licorice, popcorn, roasted nuts, or sunflower seeds.
