How to Plant, Grow, and Care For Blue-Eyed Grass

Contrary to what its name implies, blue-eyed grass is not actually related to grass. Rather, it is an herbaceous perennial and a member of the iris family (Iridaceae). The thin-bladed leaves resemble grass, and mature clusters closely resemble clumps of sedge when not in flower.

There are over one hundred species of Sisyrinchium, which are highly varied and adapted to many different regions and climates. In addition, there are numerous cultivars adding even more variations. This article will focus primarily on Sisyrinchium angustifolium, which is common and widespread throughout eastern North America. 

At the peak of its springtime flowering, blue-eyed grass puts on a showy display. Because of the densely growing habit of this plant, your patch will feature lush green foliage and an array of bluish-purple star-like flowers for you to enjoy. Each year, you can expect your patch to spread, growing larger and even more attractive.

This versatile plant is easy to grow and can be used in a variety of gardening styles. Are you looking for an addition to your cottage garden, pocket prairie, or rain garden? Try blue-eyed grass. As a plus, it blooms reliably in the spring and attracts an assortment of springtime pollinators. 

Now, let’s dig a little deeper into the use, care, and maintenance of these charming and highly diverse plants. 

Plant Natural History

Blue-eyed grass (S. angustifolium) is an herbaceous perennial wildflower native to eastern North America from Canada south to Florida and east to Texas. There are over one hundred unique species, as well as several cultivars. Other species are found throughout North and South America, including several with very small native ranges and others with such small populations that they are listed as rare and endangered. 

The common eastern variety grows naturally in moist open woodlands, along forested streams, and in moist ravines. It is most commonly found in areas with at least some dappled shade rather than fully exposed sunny areas. Most importantly, it grows in areas with consistently moist soil. Each unique species will be well-adapted to its own natural habitat.

Many species are perennials, although there are others that are short-lived perennials or annuals. These plants typically bloom in the spring and attract pollinators. Blue-eyed grass has become a popular landscaping plant because of its unique appearance, versatility, and ease of growth. 

Characteristics

The common eastern blue-eyed grass generally grows between one and two feet tall. It has thin, grass-like leaves and grows in dense clusters, spreading slowly by self-seeding and rhizomes. Over time, clusters can grow very densely, blocking out weeds and creating an effective ground cover. 

This plant typically blooms in the springtime. Depending on the variety, location, and climate, it may bloom anywhere from late winter through early summer. The flowers open singly atop thin grass-like flowering stems. These come in shades of pale blue to lavender purple. Some varieties, however, have white flowers or even yellow flowers. Some are very robust-looking, while others have a very delicate appearance. They generally all have prominent yellow centers.

After flowering, you will be left with the grass-like leaves for the rest of the summer growing season. In mild climates, some species stay semi-evergreen, although the foliage will start to look a bit weak and ragged by the end of winter before new growth appears. 

How to Grow

This wildflower is very easy to grow in any location with moderate sunlight and moist soil. Once established, these plants require very little maintenance other than occasional thinning or trimming if the clumps begin to look unkempt. 

Sunlight

Choose a location with full sun or partial shade. Ideally, it should receive at least two hours of direct sunlight per day. In hot climates, these plants appreciate some shade. In cooler climates, they perform very well in full sun.

Water

Blue-eyed grass needs consistently moist soil that does not dry completely. During times of drought, you may need to provide some supplemental watering. Because these are wild plants, they do best with deep, slow watering. Opt for a trickling hose, soaker lines, or drip irrigation.

Soil

The soil for your blue-eyed grass should be average to rich in organic matter. It needs to be well-drained so your plants aren’t sitting in soggy soil, but it should also hold some moisture during the growing season. Keep the soil pH neutral to slightly acidic.

Climate and Temperature

Blue-eyed grass is hardy in USDA Zones 4 through 9. It does well in both warm and cool climates with varying humidity levels. Any species, perennial or annual, die back in winter freezes. Blooming will cease in hot summers.

Fertilizing

Blue-eyed grass does not require supplemental fertilizer to perform well. If you are concerned about your soil quality or have particularly nutrient-poor soil, add a thin layer of organic compost around your plants each spring to give them a gentle nutrient boost. The compost will maintain a consistent level of soil moisture.

Maintenance

Blue-eyed grass is very low maintenance. If your larger clusters start looking messy or overgrown, trim the foliage or divide them and replant smaller clusters. Don’t mow the leaves low like your grassy lawn after these plants bloom. The leaves are needed to for photosynthesis. 

Garden Design

Blue-eyed grass is a versatile plant for landscaping. It is a clump-forming perennial wildflower that is easily incorporated into a woodland, wildflower, or prairie garden. Because it tolerates some shade, it is an excellent addition to a moist woodland garden or a shaded border. 

Clusters slowly spread outward over time, making this plant an effective ground cover. It won’t spread aggressively, however, so don’t worry about it taking over your garden. Grow it in a moist, partially shaded rock garden where its thin, bright green foliage complements a variety of other foliage types. 

Regardless of which type of garden you are creating, place your blue-eyed grass in a location where you can see it and fully appreciate it. This attractive plant deserves a place near the front of your gardening area where it won’t be blocked from view by taller plants. Because of its compact form and low stature, it is easily used as an edging along pathways and borders.

Varieties

There are many beautiful varieties, a few of which are listed below. Each is best adapted to the environments where they are found naturally. No matter which region of the country you live in, you are likely to find a species that is well-suited to your local climate conditions. 

Western Blue-eyed Grass, Sisyrinchium bellum

Western blue-eyed grass is native to California and Oregon. This plant grows to one foot tall and has showy purple flowers that bloom in the winter and spring. If you live on the West Coast, this species performs best in your regional climate. 

Annual Blue-eyed Grass, Sisyrinchium rosulatum

Annual blue-eyed grass is native to the southeastern United States. This is an annual species that has either pink or very pale white-blue flowers that bloom in the spring. This variety readily reseeds itself in warm climates, so expect to see it blooming in your garden each year.

Alaska Blue-eyed Grass, Sisyrinchium littorale

Alaska blue-eyed grass is a compact species growing up to about 16 inches tall. It has showy purple and blue flowers with bold yellow centers and blooms in early spring. It is native from Alaska south to Washington state. 

Mountain Blue-eyed Grass, Sisyrinchium montanum

The mountain blue-eyed grass, also known as strict blue-eyed grass, is native across the northern United States and Canada. This species has thin, dark green leaves and dark purple-blue flowers that bloom in the spring. This species is a great option for colder climates.  

Dwarf Blue-eyed Grass, Sisyrinchium minus

The dwarf blue-eyed grass is an annual species native to a few scattered southern states. It grows only six to nine inches tall and has purplish flowers that vary from almost white to a deep mauve color. These compact plants perform well in warm climates and readily reseed themselves for continued growth year after year.

Wildlife Value

Blue-eyed grass blooms in the springtime and attracts pollinators. You may see native bees and an occasional early-season butterfly visiting the flowers. Because they typically bloom before many other flowers, this plant is a valuable addition to your pollinator-friendly landscape. 

Common Problems

This plant is remarkably trouble-free. You are unlikely to have any issues with pests or diseases. Just make sure the soil is well drained. Plants sitting in consistently wet soil are likely to rot.

Propagation

Blue-eyed grass is easy to grow and easy to propagate. Plants are best grown from seed or by division of mature clusters. Since these are popular with gardeners, you also sometimes find young starts at nurseries and garden centers, particularly those that specialize in native species.

Seed

Although this method requires a bit of patience, blue-eyed grass can be successfully grown from seed. The seeds typically require a phase of cold stratification before they germinate. The easiest way to do this is to grow your plants under natural environmental conditions. If you buy seeds in a packet, directly sow them outside in late fall. 

The seeds overwinter and germinate in the spring with the onset of warmer weather and moist soil conditions. Young plants very much resemble small blades of grass. Keep the seeds and young plants moist, and do not allow them to dry out. If you have problems with squirrels or other small animals digging into your soil, protect your seeds and seedlings with a critter cage.

Division

Dividing your clumps is the easiest and most successful way to propagate blue-eyed grass. If you have a mature cluster, dig it up in the early spring or late fall and divide it into just a few or several new clumps.

Each new clump can then be replanted or transplanted to new locations. After dividing, water your new transplants well to help them recover from transplant shock. 

Transplanting

If you have a potted plant, you’ll eventually transplant it into a permanent location in your garden. The best time to do this is during the early spring or fall when the weather is cool and mild. 

Identify the location where you will put your plants and prepare the soil by digging a hole slightly larger than the pot. Carefully remove your blue-eyed grass from its pot and gently place it in the hole so that the ground levels match. Then, fill any gaps around the edges with fresh soil and pat it down around the plant. Finally, give it a thorough watering and keep your newly transplanted plants moist. 

Frequently Asked Questions