Blackhawks Bluestem Grass – Transform Your Landscape With Dramatic
Blackhawks bluestem grass is a premier ornamental cultivar of the native Big Bluestem (Andropogon gerardii), prized for its upright habit and stunning color transition from dark green to deep purple-black. It thrives in full sun, requires minimal water once established, and serves as an excellent low-maintenance focal point or privacy screen for USDA zones 3 through 9.
Finding a plant that offers both architectural structure and evolving seasonal color can feel like a daunting task for any homeowner. Many ornamental grasses look great in summer but lose their luster or flop over as soon as the weather shifts.
If you are looking for a “set it and forget it” solution that actually improves as the season progresses, incorporating blackhawks bluestem grass into your garden is the answer. This plant provides a vertical punch and a dramatic color palette that few other perennials can match.
In this guide, I will walk you through everything you need to know to grow, maintain, and design with this spectacular native grass. From soil preparation to seasonal pruning, you will learn how to make this plant the star of your landscape.
What Makes Blackhawks Bluestem Grass a Landscape Game-Changer?
As a professional landscaper, I have seen many cultivars come and go, but this specific variety of Big Bluestem stands out for its resilience. Unlike the wild species which can sometimes become “leggy” or fall over in rich soil, this cultivar stays tight and upright.
The most striking feature is undoubtedly the foliage color. In early spring, the blades emerge with a subtle dark green hue, often tinged with bronze. As the heat of summer intensifies, the plant begins its transformation into deep purples and violets.
By the time autumn arrives, the grass reaches a nearly black intensity. This provides a stark, beautiful contrast against the oranges and yellows of typical fall foliage. It reaches a manageable height of 4 to 5 feet, making it perfect for mid-border placements.
The Benefits of Native Cultivars
Choosing native-based plants like this one supports your local ecosystem. This grass provides essential nesting material for birds and serves as a host plant for several species of butterflies and skippers.
Because it is a selection of a native prairie grass, it possesses an incredibly deep root system. These roots can reach several feet into the earth, allowing the plant to find moisture during intense droughts that would kill off more delicate garden plants.
It also acts as a natural soil stabilizer. If you have a sloped area in your yard prone to minor erosion, the dense root mass of this grass helps hold the earth in place while looking far better than plain riprap or plastic netting.
The Ideal Growing Conditions for Your Ornamental Grass
To get the best performance out of your plants, you must mimic their natural prairie environment. This means prioritizing sunlight and drainage above all else.
Place your plants in a location that receives at least six to eight hours of unfiltered sunlight daily. If you plant them in partial shade, the stems will weaken, and you will lose that signature deep purple coloration.
While this grass is adaptable to various soil types, including heavy clay, it performs best in well-drained soil. If your yard holds water like a sponge after a rainstorm, consider planting on a slight mound or incorporating organic matter to improve drainage.
Understanding Soil Fertility
One of the biggest mistakes DIY gardeners make is over-fertilizing their ornamental grasses. This plant actually prefers “lean” soil with moderate to low fertility.
High levels of nitrogen (the first number in an NPK ratio) will cause the grass to grow too quickly. This results in weak, succulent stems that cannot support their own weight, leading to a “flopping” effect that ruins the aesthetic.
I recommend skipping the synthetic fertilizers entirely. A thin layer of leaf mulch or a light dusting of compost in the spring provides more than enough nutrients for the entire growing season.
Step-by-Step Planting Guide for Success
The best time to plant is in the spring or early autumn when temperatures are mild. This allows the root system to establish before the stress of extreme summer heat or winter freezes.
- Prepare the site: Remove all weeds and existing turf from a 3-foot diameter circle. This reduces competition for water and nutrients.
- Dig the hole: Make the hole twice as wide as the nursery pot but no deeper. You want the top of the root ball to be level with the surrounding soil.
- Tease the roots: If the plant is root-bound (roots circling the inside of the pot), gently tease them outward with your fingers to encourage outward growth.
- Backfill and tamp: Fill the hole with the original soil. Use your hands to firm the soil down, removing large air pockets without compacting it too tightly.
- Water deeply: Immediately after planting, give the grass a thorough soaking to settle the soil around the roots.
Spacing is critical if you are planting a row. Space each plant 24 to 36 inches apart on center. This allows for adequate air circulation, which prevents fungal issues during humid summer months.
Apply a two-inch layer of wood mulch around the base, but keep the mulch from touching the actual stems of the grass. This prevents moisture from rotting the crown of the plant.
Seasonal Care and Maintenance Routine
One of the reasons I frequently recommend blackhawks bluestem grass to my clients is the minimal maintenance required. Once the plant is established (usually after the first full growing season), it is incredibly self-sufficient.
During the first year, water the plant once a week if there is no significant rainfall. After the first year, you should only need to water during prolonged dry spells or extreme heatwaves.
The most important maintenance task happens in late winter or very early spring. You must cut the previous year’s growth back to about 3 to 5 inches above the ground before new green shoots appear.
Pruning and Tool Safety
Using the right tools makes this job much easier. A pair of sharp bypass pruners or a set of hedge shears works best. For larger stands of grass, some gardeners use a string trimmer with a blade attachment.
Safety is paramount when handling tall grasses. The edges of the blades can be surprisingly sharp and may cause small “paper cut” style irritations on your skin. Always wear sturdy work gloves and long sleeves when pruning or handling the foliage.
Bundle the dry stems together with a piece of twine before cutting. This makes the cleanup much faster and prevents the dead grass from blowing across your lawn. You can compost these stems or use them as mulch in other parts of the garden.
Landscaping Design Ideas and Companion Plants
Because of its vertical habit, this grass acts as an exclamation point in the garden. It is an ideal choice for the “thriller” component in large container displays or as a backdrop for shorter perennials.
Consider planting it in a “matrix” style where it is scattered among lower-growing plants. This mimics the look of a natural meadow. It also works beautifully as a low-maintenance privacy screen along a patio or property line.
The dark foliage provides a perfect foil for plants with silver, gold, or bright green leaves. The contrast makes both plants “pop” visually, creating a professional-looking landscape with minimal effort.
Best Companion Plants
- Rudbeckia (Black-eyed Susans): The bright yellow petals create a stunning contrast against the dark purple stems.
- Echinacea (Coneflowers): These hardy perennials share the same water and light requirements, making them perfect neighbors.
- Little Bluestem: Mixing different heights and textures of bluestem creates depth and visual interest in a prairie-style garden.
- Sedum ‘Autumn Joy’: The succulent leaves and late-season pink blooms complement the fall color shift of the grass.
When designing, think about the “winter interest” as well. Do not cut the grass back in the fall. The dried, dark seed heads and sturdy stems look beautiful covered in frost or light snow, providing much-needed structure to a dormant garden.
Troubleshooting Common Issues and Pests
While blackhawks bluestem grass is generally pest-resistant, it is not entirely immune to problems. Most issues stem from environmental stress rather than insects or disease.
If you notice orange or brown pustules on the leaves, your plant may have rust. This fungal disease usually occurs during exceptionally wet, humid summers. To fix this, improve air circulation by thinning out nearby plants and avoid overhead watering.
Another common issue is “lodging,” which is when the grass falls over. This is almost always caused by too much shade, too much water, or excessive fertilizer. If your grass flops, trim it back and resolve the underlying soil or light issue for the next season.
Dealing With Wildlife
Deer and rabbits generally find this grass unappealing because of its coarse texture. However, in early spring, hungry rabbits might nibble on the tender new shoots. If this happens, a light application of a natural repellent can deter them until the grass grows taller.
On the positive side, you will likely notice an increase in bird activity. Sparrows and finches love to eat the seeds in late fall. This provides a natural food source for them when other insects and seeds are scarce.
Safety and Environmental Responsibility
As gardeners, we have a responsibility to use tools and chemicals safely. If you choose to use herbicides to clear a planting area, always read the label and wear protective gear, including eye protection and chemical-resistant gloves.
However, for a plant like this, manual weeding is usually the better, safer option. Using a garden fork to lift out stubborn perennial weeds ensures you don’t leave chemicals in the soil that could affect the native root systems.
Maintaining blackhawks bluestem grass is surprisingly simple, but being mindful of your environment ensures the plant thrives for decades. Avoid using heavy machinery near the base of the plant to prevent soil compaction, which can suffocate the deep roots.
Frequently Asked Questions
How Fast Does Blackhawks Bluestem Grass Grow?
In its first year, it focuses on root development and may stay relatively short. By the second and third years, it will reach its full height of 4 to 5 feet by mid-summer. It is a moderate-to-fast grower once the roots are established.
Can I Grow This Grass in a Pot?
Yes, but you need a very large, heavy container. The deep root system requires space, and the height of the grass can make lightweight pots tip over in the wind. Ensure the container has excellent drainage holes.
Is This Grass Invasive?
No, it is a clumping grass, not a running one. While it may drop seeds that produce a few volunteers, it does not spread via aggressive underground rhizomes like some invasive species. It stays exactly where you plant it.
Does It Need to Be Divided?
Every 4 to 5 years, you may notice the center of the clump beginning to die out or look thin. This is the time to divide it. Use a sharp spade to lift the entire clump in early spring, cut it into sections, and replant the healthy outer portions.
Conclusion
The beauty of blackhawks bluestem grass lies in its ability to provide high-impact visual drama with very little input from the gardener. Its transformation from green to nearly black is one of the most rewarding sights in a late-season landscape.
By following the simple steps of providing full sun, avoiding over-fertilization, and performing a single annual pruning, you can enjoy this native powerhouse for years. It is a testament to the fact that the most beautiful gardens are often the ones that work with nature rather than against it.
Now is the perfect time to evaluate your garden beds and find a sunny spot for this dramatic grass. Your local pollinators—and your neighbors—will thank you for the stunning addition to the neighborhood.
Taylor pairs an engineer's eye with years of hands-on work in soil, lawns and outdoor machinery. He tests ideas in his own garden, keeps tractors and mowers running himself, and speaks to local horticulture groups. Every Garden Aider guide is written to be practical, accurate and safe to follow.
“To bring life alive, you just need to mix some love with the compost, bedding, and gardening machines.”