How to Grow and Care for Liatris (Blazing Star)

Liatris, also known as blazing star or gayfeather, is a long-blooming perennial wildflower. It has highly unusual flower heads featuring tiny and colorful star-like blossoms arranged around a long upright bottlebrush spire.

The grasslike leaves are narrow and inconspicuous, forming a basal clump, but they turn an attractive bronze color in the fall. Blazing star is adaptable to many warm and cold climates and requires full sun, and well-drained, slightly acidic soil but prefers drier winter conditions.

Blazing Star Care

Here are the main care requirements for growing blazing star:

• Plant blazing star corms in the spring after the last frost date spaced 12 to 15 inches apart and two to four inches deep.
• Place corms in well-draining soil that's slightly acidic or neutral.
• Avoid planting in clay or overly rich soil for best results.
• Put blazing star plants in full sun.
• Water new plants or corms thoroughly, and then water only during the hottest months.
  

Light

Choose a site with full sun to plant blazing star corms. These are prairie plants in their native habitat, so the more sun, the better they will perform.

Soil

Just about any soil, at any level of fertility, will successfully grow blazing star corms, although quick drainage is essential to prevent rot. Very rich soils may require that you stake the plants, as the stalks can be a bit floppy.

Blazing star prefers a slightly acidic to neutral soil pH. Heavy clay can cause root rot, especially in winter, if the soil doesn't drain well.

Water

After planting, water the corms thoroughly. The corms do not need additional irrigation until stalks sprout. As the plants begin active growth, one inch of water a week during the hottest months will prevent stunted flowers and leaf scorch.

Apply water to the base of the plants, or use drip irrigation, to avoid spreading fungal diseases. These plants need more water in their first year; afterward, they have good tolerance to drought and dry soil conditions.

Temperature and Humidity

Hardy in zones 3 to 9, blazing star is quite tolerant of summer heat and humidity in warm climates and will survive very cold winters, provided that the soil is not too wet. Wet winter soils can cause the corms to rot.

Fertilizer

Blazing star is not a heavy feeder, but if the soil fertility is poor you can apply a balanced flower fertilizer each spring as active growth begins. In most decent soils, however, it usually does fine with no feeding whatsoever.

Types of Blazing Star

L. spicata, the most common garden species, is very often planted in its original native form. Several named cultivars are popular, and there are also a couple Liatris species of note:

• ‘Alba’: This cultivar has pure white flowers and grows about 18 inches tall.
• ‘Callilepsis’: This cultivar has the expected purple flowers on especially long stems that are ideal for cut flower arrangements.
• ‘Kobold’: This is a smaller, more compact variety with deep-purple flower heads. This variety is a good choice for the foreground of mixed perennial beds.
• 'Floristan White' and 'Floristan Violett': These cultivars have beautiful, 3-foot flower spikes that bloom in July and are known for having an especially long bloom period.
• 'September Glory': This plant blooms from August to September with 4-foot purple spikes.
• L. aspera (rough blazing star): This species has purple flowers that grow from 15 to 40 inches tall, depending on location. It has less showy flowers but is a good performer for dry, barren soil.
• L. pycostachya (prairie blazing star or Kansas gayfeather): This plant blooms later, in August through September. It is available in white, purple, or rose-purple flowers that grow on spires reaching two to five feet tall.
  

Propagating Blazing Star

As blazing star matures, it typically develops offset corms. It's easy to propagate this plant by digging up the root corms and separating them. Doing this every few years will also help rejuvenate the plants and extend the life of a clump. Here's how:

1. In spring as new growth is just beginning, use a shovel or trowel to dig up the entire clump.
2. Separate the clump into sections, each with at least one thick corm with at least one "eye" or bud.
3. Discard any corms that are soft or completely desiccated.
4. Plant the corms immediately in their new locations, after carefully loosening the soil to at least five inches deep.
5. Space pieces at least 1 foot apart to ensure good air circulation. Corms can also be divided in fall, and then stored over winter for spring planting.

How to Grow Blazing Star From Seed

Blazing star can also be grown from seed, although patience is required since the first blooms take two years or more to appear. The seeds will require four to six weeks of cold stratification to germinate.

If starting seeds indoors, take these steps:

1. Plant the seeds in small pots or starter trays filled with standard potting mix.
2. Moisten the mix, then plant the seeds in groups of three to five seeds, just barely covering them with additional potting mix.
3. Place the containers in a spot that receives morning sun and where nighttime temperatures remain above 50 degrees Fahrenheit.
4. Continue to moisten the potting mix until the seeds sprout, which usually takes two to four weeks.
5. Keep the seedlings moist as they grow in a sunny location until it's time to transplant them outdoors after all danger of frost has passed.
6. Harden off seedlings before planting them in the garden. New seedlings may need protection from feeding rabbits for the first year.

Potting and Repotting Blazing Star

Native perennials such as blazing star are not commonly grown in containers, but it is certainly possible to do so. Any well-draining container filled with a good porous potting mix will work.

Planting and care are identical for in-ground plants, but you will probably need to water more often, as the soil in containers tends to dry out faster than garden soil.

To ensure winter survival, move the containers to a sheltered location as freezing weather approaches. Some gardeners have had success placing containers in a cold frame or cool garage, heaping them with mulch, or even burying the container in the garden for winter.

Don't try to bring a potted blazing star indoors to grow as a houseplant over winter, as these plants require weeks of cold dormancy to reset themselves for spring growth.

Overwintering

Within its hardiness range, blazing star does not need any special winter cold protection. The normal pruning routine is simply to cut off the flower stalks near ground level, though you can also leave the flower heads in place for the benefit of winter-feeding birds.

Blazing star does not like wet winter soil so avoid heaping mulch over the plant crowns for the winter, as this can trap moisture and encourage bulb rot. Make sure to clean away soggy garden debris in the spring before new growth begins.

Common Pests & Plant Diseases

Blazing star does not suffer from any serious insect problems, but several fungal diseases can occur, including leaf spot, rust, stem rot, powdery mildew, and verticillium wilt. The best approach is to prevent these diseases by giving the plants good sunlight and air circulation.

Mild fungal diseases, such as leaf spot and powdery mildew, are usually not serious and may not even require treatment. More severe diseases sometimes can be treated with fungicides, but it may be necessary to remove and destroy badly affected plants.

How to Get Blazing Star to Bloom

Bloom Months

Blazing star typically blooms from July into late fall. Young plants sometimes withhold flowers for the first year or two until the root systems become well established.

What Do Blazing Star Flowers Look and Smell Like?

The pure species has bright purple flower spikes, but there are also pink and white cultivars available. Fresh blazing star does not have any scent, but dried flowers may emit a faint vanilla fragrance.

How to Encourage More Blooms

The largest corms will produce the most impressive flowers. For better blooms, start by choosing corms that approach three inches or more in diameter. These structurally swollen dormant stem parts will send up shoots followed by flowers approximately three months after a spring planting.

If mature plants fail to bloom at all, it may be a problem of soil fertility. Try blending in a slow-release fertilizer into the soil around the plants each spring. Also, check to ensure the plant receives enough sunlight.

Deadheading Blazing Star Flowers

Deadheading blazing star after the first bloom of the year may encourage a second blooming. Do not deadhead any blooms if you want the plants to reseed.

Common Problems With Blazing Star

As a hardy native wildflower, blazing star generally thrives with relative neglect. When problems occur, it is often the result of too much care—too much soil fertility or too much watering.

Flower Stalks Flop Over

Blazing star is a sturdy plant, even when growing in average or poor, rocky, gravelly soil. In most cases, staking the plants is not necessary. Paradoxically, rich, fertile soils can cause the flower stalks to topple over. In this case, you may need to stake up the flower stalks.

Plants Turn Mushy and Break

Mushy plants that break at the ground level indicate stem or corm rot, which is caused by wet soil that introduces fungal disease into the roots or stems. Unfortunately, these plants will need to be removed. Future problems can often be avoided by reducing water or improving soil drainage.