Ornamental · Asteraceae
Blazing Star
Liatris spicata
From a rounded corm, blazing star lifts tall purple spikes for the bees each summer.
Full sun
USDA 3–8
2–4 ft · 0.6–1.2 m
Overview
Blazing star is a North American prairie native built on vertical lines. Rather than a wide, flat flower, each plant throws up a tall, slender spike, and along its upper length sit dense purple buds packed so tightly they open into a soft, fuzzy column of bloom. Below, thin grass-like leaves clothe stiff stems, and when a stand comes into flower the fuzzy purple columns hum with butterflies and bees. It rises from a rounded corm, comes back on its own each year, and asks little once its roots take hold.
The bloom carries a quirk you can watch unfold. Most spike flowers open from the bottom up, but blazing star opens from the top down, so the crown of the column fades while the lowest buds are still splitting into purple threads. Those narrow leaves and rigid stems draw sharp vertical strokes against rounder plants, whether you grow the full-height species or a shorter, denser selection like 'Kobold'.
Its physical toughness matches its looks. Set in full sun and ground that drains, the corm and its tuberous roots shrug off heat, drought, and lean soil once they are established. The one thing that undoes the plant is wet feet in winter, which turns the firm corm soft and rotten faster than any pest or disease.
Care
The short version: full sun and average, well-drained soil, regular water the first season and far less after, and a site that never stays soggy through winter.
Light
Give blazing star full sun. In partial shade the thin stems stretch pale and weak and lean out of line, so the more sun that reaches them, the thicker and more upright the spikes stand.
Water
Water it through the first growing season to settle the corm and its roots. After that it runs fairly drought tolerant and needs little, and it would far rather sit dry than wet, above all through winter when standing water rots the corm.
Soil
It takes almost any well-drained soil, from loam to sand to clay, and holds on even in poor ground. A pH anywhere from 6.0 to 8.0 suits it, so drainage, not richness, is what its corm cares about.
Humidity
Plain outdoor air is all it asks, and no target range applies. Moving air matters more here, since crowded, still conditions let a powdery film of mildew and rusty pustules settle on the leaves.
Feeding
This lean-soil prairie plant is not a heavy feeder. A light feeding before the shoots break ground in spring is plenty, and too much fertilizer only draws out soft, floppy stems that cannot hold their heavy spikes up.
Pruning
Cut the faded flower stalks once the color is gone, but leave the leaves and hollow stems standing through winter to shelter native bees and feed songbirds on the dry seed, then cut them back in early spring. Tall stems in rich, moist soil may need a stake.
Size & spacing
The stems climb 2 to 4 feet (60 to 120 cm) in a narrow, upright clump. Set the corms about 12 to 15 inches apart so air slips between the spikes and each one has room to stand.
When to plant
Blazing star is a hardy perennial for zones 3 to 8. The rounded corms or young plants go out in early spring, container-grown stock again in early fall, and the purple spikes rise in mid- to late summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Early spring; seed germinates in 20-45 days and benefits from 4-6 weeks cold moist stratification
- Plant: Plant corms or container plants in early spring; container-grown plants may also be set out in early fall, spaced 12-15 inches apart
- Harvest: Blooms mid- to late summer (July-August), with dense purple flower spikes opening from the top down
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Blazing star runs into few real problems, and nearly all of them trace to one thing: ground that holds too much water. Watch the thin leaves and stiff stems through the season, and step in early before a fleck of fungus or a softening corm spreads. Match what you see below, then act while it still helps.
A wilting clump over a soft, rotting corm
When the stems go limp and topple, the rounded corm below has often turned soft and mushy with stem and corm rot, which sets in where wet, poorly drained soil stays saturated through winter. A rotted corm cannot firm back up, so it is dug out with the tainted soil around it. Drainage is the cure: blazing star belongs only where water runs off and never pools.
Fix:
- Improve drainage and avoid wet sites
- Remove and discard affected plants and surrounding infected soil
Tall flower stems bowing and bending over
When the stems arch and sag under their spikes, the tissue behind them is soft, weak growth, drawn out by soil that runs too rich or too damp and slackened further by shade. Full sun and leaner ground stiffen the stalks, a stake props the tallest, and a short, thick-stemmed cultivar like 'Kobold' stays upright on its own.
Fix:
- Stake or provide support for tall stems
- Site in full sun and average, well-drained soil rather than rich, moist beds
- Choose compact cultivars such as 'Kobold'
A chalky white film dusting the leaves
A pale, floury bloom that dulls the green blades is powdery mildew, a fungus that spreads late in the season where stems crowd together and the air sits motionless. Spacing or thinning the clump lets air slide between the leaves again, and stripping the most coated blades leaves the fungus less surface to colonize.
Fix:
- Improve air circulation by spacing and thinning plants
- Remove and dispose of badly affected foliage
Orange to brown pustules stippling the leaf backs
Small raised bumps in rusty orange to brown, clustered on the undersides of the narrow blades, are the spore heads of rust fungi. Picking off and burning the spotted leaves clears the source before the powdery spores drift, and wider spacing keeps air sliding past so the foliage dries fast once the rain lets up.
Fix:
- Remove and destroy infected leaves
- Improve spacing and air circulation
Toxicity
Good news for pet owners and parents: blazing star is safe all around. The ASPCA lists it as non-toxic to cats, dogs, and horses, and nothing in the grassy leaves, hollow stems, or rounded corm poisons people or grazing animals. The most a big mouthful is likely to cause is a passing stomach upset.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists blazing star as non-toxic to cats, so a mouthful of the narrow leaves does no harm. A cat that gorges on any plant may bring it back up, but that is the coarse, grassy blades scratching at the stomach, not poison.
Dogs None
Dogs are safe with it too, since the slender leaves, hollow stems, and rounded corm carry no toxic compounds. The most a big mouthful is likely to bring is a passing bout of mild stomach upset.
Horses None
Horses can graze on the grassy foliage without harm, as blazing star holds nothing poisonous to them.
Rabbits None
Rabbits and other small pets can nibble the thin, upright leaves safely. It is a wildflower they would crop in the meadow anyway.
Livestock None
Cattle, goats, and sheep take no harm from the leaves or stems in the pasture, since blazing star holds no toxins that trouble grazing animals.
Birds None
Birds are safe around it, and songbirds like goldfinches pick the small ripe seeds from the faded spikes through fall and winter.
People None
No part of blazing star, from the purple florets to the corm, is poisonous to people. It is grown for its flowers rather than the table, so there is no reason to eat it, but a stray touch or taste does no harm.
Varieties
Most of the named blazing stars are picked for the color of their spikes or for a shorter, denser habit. These are the ones you are most likely to find.
Kobold
A compact selection with deep-purple spikes that stays short enough to hold its stems bolt upright, which sets it at the front of a border.
Floristan White
A form whose spikes open clean white rather than purple, prized for cutting because those pale columns keep their shape in a vase.
Floristan Violett
A selection with violet spikes on stems stiff enough to cut and carry, which is why it turns up so often in florists' hands.
Alba
A pure white form whose spikes top out around 18 inches, shorter than the species and easy to slot into a small bed.
How to propagate
You can make more blazing star by splitting the corms of an established clump or by starting from seed, though one lifts a flower spike far sooner than the other.
DivisionEasy
Spring, just as leaves emerge · Establishes over one to two seasons; clumps can be divided every few years
Dividing an established clump is the surest route to more plants. In spring, just as the first grassy shoots break the soil, the clump is lifted and the rounded corms and their tuberous roots are pulled or cut apart, each piece keeping at least one eye. The divisions come up true to the parent, though they settle in slowly and take a season or two to bulk out into a full clump.
SeedModerate
Early spring indoors or direct sow, or fall sow outdoors · Seedlings typically bloom in their second or third year
Seed asks for patience. The small seeds sprout in 20 to 45 days, but only after a cold spell wakes them, so they take 4 to 6 weeks of cold, moist chilling first, or a fall sowing outdoors where winter does the chilling. From there a seedling grows a thin tuft of leaves and waits until its second or third year before it lifts its first flower spike.
Myths
Blazing star is poisonous to dogs and cats.
The ASPCA lists blazing star among the plants that are not toxic to dogs and cats. As with any plant, a pet that swallows a big mouthful of the grassy leaves might get a mild upset stomach, but there is no poison in them.
Liatris spikes open from the bottom up like most spike flowers.
Blazing star does the reverse of nearly every other spike flower. It blooms from the top of the spike downward, so the crown of buds is already fading to a faded purple while the lowest ones are still cracking open.