Rough Blazing Star, A Complete Guide For Liatris Aspera

If you are a fan of blazing stars, you are probably aware that there are quite a few different species that fall under this genus. And while all generally have some form of purple-lavender flowers, each is a bit unique. Well, this particular species, commonly known as Rough Blazingstar should find it’s way to your garden as it can extend the time you get to enjoy those purple flowers, as it is almost always the last of them to bloom.

Rough Blazingstar is a perennial wildflower native to Central North America. Scientifically known as Liatris aspera, it grows 3-5′ tall in full sun and well draining soil. Blooming purple, button-shaped clusters of flowers for 3-4 weeks in late summer to early fall, it attracts numerous species of bees, butterflies, and moths^[1][2][3].

I’ve been growing this species (and others) of Liatris for many years now, and will share everything I’ve learned with you. From harvesting seed from the plant, germination, establishment, as well as where to locate them and care for them, I’ve got it all in this article.

Native Range

The predominant native range of Rough Blazingstar is from Texas/Louisianna North to North Dakota and Minnesota, and even creeping into parts of Southern Canada. Isolated populations also dot the Appalachian Mountains and Southeastern United States^[1].

It is naturally found in prairies, particularly those with sandy soil. Also along roadsides, railroads, savannahs, and the border of forests^[2][3].

Reference Table

Scientific Name	Liatris aspera
Common Name(s)	Rough Blazing Star, Button Blazing Star, Tall Blazing Star, Rough Gayfeather
Lifecycle	Long-lived perennial (30+ years)
Native Range, USDA Zone	Central North America, USDA Hardiness Zones 3-8
Bloom Time	Late Summer to early Fall
Bloom Duration, Color	3-4 weeks, purple to lavender
Height	2-4′ tall
Spacing / Spread	1-2′
Light Requirements	Full sun to part-sun
Soil Types	Sandy loam to clay-loam, rocky. Grows best in poor soils.
Moisture	Medium-moist to dry soils
Fauna Associations / Larval Hosts	Bees, butterflys, hummingbirds. Hosts at least 1 moth

Benefits

Beauty

Like other members of the Liatris genus, Rough Blazing Star has a stunning beauty. The pastel lavender blooms pair nicely with Asters and contrast against evergreens and grasses just before they begin to turn a golden brown. Truly a stunning pop of late season color, that also has an incredibly interesting and unique flower structure.

Late bloomer

Look, I grow six different species of Liatris. But this one is easily the last of them to bloom, each year. If you love the purple spikes of the more common Blazing Star, try this one to extend the amount of time you get to enjoy the flowering spikes.

Drought tolerant

This particular species of Liatris is drought tolerant. It will do great in fast draining soils and slopes where some other species struggle.

Wildlife

Like all species of Liatris, this one also is irresistible to bees and butterflies. Clusters of this flower will undoubtably attract all manner of bees from your area as well as passing butterflies.

Identification and Characteristics

Stalk

The stalk is generally erect and doesn’t lean in wild areas. In areas with fertile soil it may lean/flop^[3]. The color will be green to red (later in year) and have lots of small hairs. Several stalks can emerge from a single corm (bulb) as the plant matures.

Leaf

Alternate, linear to lanceolate leaves are up to 12″ long by 1″ wide. The size of leaf decreases as it ascends the stalk, and the color is some shade of green to blue-green^[3].

Flower

The flowers ascend the stalk in alternating clusters that are separated. So, you basically have a tall spike that has these groups of small flowers that are clustered, resembling a sphere, where half of the sphere are the blooms.

Other forms of Liatris have more of a continuous inflorescence, while this one has clear separation between the clusters of flowers. This structure was the primary influence in the common names of Rough Blazingstar or Button Blazingstar.

Root

The root system is fibrous roots emerging from a woody corm. This corm is similar to other forms of Blazingstar, namely L. ligulistylis, L. pycnostachya, and the most common Blazingstar, Liatris spicata.

Growing Conditions

Sunlight Requirements

Rough Blazingstar will grow best in full sun. It can grow in part-sun, but the plant size/height will be less, and it will not be as showy.

Soil Requirements

For soil, this plant will do best in poor, infertile soils. It should drain well, so sandy-loam to clay-loam will be best for it^[3].

Moisture Requirements

For moisture, dry to medium-moist soils are preferred.

Maintenance

The only maintenance for this plant is to cut the stalks back to 6-12″ in Autumn. It is generally disease free, but is possible to get rust^[3]. I have never seen any disease on any of my plants though.

Fertilizer

Do not fertilize this plant. Fertilizing may lead to the plant leaning or flopping over on the ground.

Saving seed

To save the seed, simply wait until about six weeks after blooming. The flower clusters will be replaced with seedheads. Each individual flower in the cluster will now have a seed with a small feather on the back. The feather helps the seed be somewhat distributed by wind.

But, cut the stalk below the seed heads. Then, while holding the stalk over a plate or bucket, run your hand over the stalk to release the seed w/ feathers. Store the seed in a sealed plastic container in the refrigerator until you are ready to winter sow the seed.

How to Grow Liatris aspera from Seed

Growing Rough Blazingstar from seed isn’t too difficult, but it has a couple of special requirements. First, the seeds need to be fresh. If they fully dry out and are stored at room temperature, then they are likely not viable. So if you purchase a packet of seeds online, then make sure you store them in the fridge, sealed^[3].

Second, the seeds need to experience a cold-moist stratification period of roughly 60 days before they can germinate^[5]. This is best accomplished via winter sowing (I do mine around Christmastime), but you can do this using a paper towel in the fridge too.

And third, the seeds need to be exposed to sunlight to germinate. So, when you actually plant them, regardless if you are winter sowing or stratifying in the fridge, just press them into the potting soil firmly, then provide a dusting of soil. But do not completely bury them. Seeds that have good contact with the soil will have no problem sending a root down.

Several weeks after germination, you can carefully separate the seedlings. It is wise to wait until the ‘grass’ like leaf is emerging from the two small cotyledons. See my guide here for how to separate seedlings. Alternatively you can transplant the seedlings to their final location when the ‘grass like’ leaf emerges. If you do this, you can often be rewarded with first year blooms, as I managed to do this the first year I germinated them. .

My rough process for making more plants is that I will harvest the seed fresh, in November-December (I’m in zone 6). I will harvest when it is dry, and store it in a zip-lock bag in the fridge until Christmas time. Then, I will either prepare a jug or pots with moist potting soil, and press the seed firmly into the soil to ensure good contact. I will water, then set out my winter sowing containers in the shade until March. In March, I will move them to a location that receives morning sun and afternoon shade.

Propagating Rough Blazingstar from division

Once a plan is several years old, you can divide the corms in early Spring as the plant begins to emerge. You need to wait until the corm is quite large, ideally 6″ diameter or more to divide it.

But to divide, as you see the plant beginning to emerge in Spring, dig out the corm. To do this, locate the emerging plant leaves. Using a spade, dig around the plant with the shovel positioned at least 2″ (5 cm) away from the plant, angled 30 degrees from vertical. Dig all the way around and ‘pop’ it out of the hole. Brush off any dirt so you can see the full size of the corm mass. Then, using a pruning saw, cut through the corm.

Replant each section to the same depth from whence you dug it out. If you do this job in early Spring, and the soil is already moist, then it probably isn’t necessary to water. This is because the temperatures are cooler, as is the soil, thus the plant will not have much water demands.

Too see more pictures, see my guide to dividing Liatris.

Wildlife, Pests, and Diseases

Pollinators

This plant, like other members of Liatris are nearly irresistible to pollinators. It has been documented to attract numerous species of long-tongue bees, butterflies, as well as others^[2][3].

Pests

This plant is susceptible from deer and rabbits. And the corms (bulbs) are sometimes dug up and eaten by mice and voles.

Deer and Rabbits

As stated above, deer and rabbits will eat the foliage. To keep them away, I strongly recommend using Liquid Fence to keep them away. Use it, follow the instructions to the letter, and you will be ok.

Where you can buy Rough Blazing Star

Rough Blazing Star is not typically sold in big box stores or traditional nurseries. But it can be purchased at specialty nurseries that deal in Native Plants. You can find native plant nurseries near you on our interactive map.

Where to buy seeds

We have ordered a variety of native flower seeds from Everwilde Farms, which you can order right from Amazon through our link on our RECOMMENDED PRODUCTS PAGE. (We may earn a small commission when you purchase through our links, at no cost to you. This helps support our website.)

Uses of Rough Blazing Star

Garden Uses

This plant can be used similarly to other Liatris, but it will do best in infertile soil that is on the drier side. It will be at home in formal flower beds or wild areas, provided the soil isn’t too fertile, as excess fertility or nitrogen can lead to the plant flopping over.

I mostly have this plant scattered throughout my ‘test strip’, and it looks great peppered in with other natives, particularly asters like Heart Leaf and Short’s Aster. The underlying soil is sandy loam that was turf grass for about 20 years, and is quite infertile. These plants are thriving though, and are even reproducing a bit via self-seeding. I should add that it doesn’t self-seed much, it is quite manageable.

Companion Plants

This plant pairs nicely with other full-sun medium to dry moist soil plants like Showy Goldenrod, certain species of Aster, and even shorter sunflowers. I have mine growing amongst Heart Leaf, Silky, and Short’s Aster and Showy Goldenrod, as they bloom concurrently. It also would work great with native grasses such as Prairie Dropseed and Little Bluestem.

Medicinal Uses

Although other species of Liatris have been used medicinally by various Native American Tribes, I could not locate any information of Liatris Aspera being utilized. So, it would appear that this plant has no medicinal uses.

Final Thoughts

If you love the flowers of the Liatris genus, then this is a species you should add to your collection for the simple fact that it will bloom later than all others. So, you will get to enjoy those colorful purple blooms longer during the growing season. And if you are gardening to support pollinators, this plant will most certainly draw attract them in huge numbers. Plant them in groups of 3-5 to make them even more attractive.

Find more native plants here