Species Brief
Centaurea solstitialis, yellow starthistle
Written
June, 2026
Contributors
Ilana L. Abrahamson - 1st Compiler, Leila Duchac - 1st Editor
Abrahamson, Ilana L., compiler. 2026. Species Brief: Centaurea solstitialis, yellow starthistle. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-briefs/censol
DOI
10.2737/feis-species-brief-censol
Scientific Name
Centaurea solstitialis
Common Names
yellow starthistle
Barnaby's star-thistle
St. Barnaby's thistle
yellow star thistle
yellow star-thistle
FEIS Lifeform Type
Forb
Kingdom
Plantae
Class
Magnoliopsida (Dicot)
Order
Asterales
Family
Asteraceae
Genus
Centaurea
Nativity
Nonnative
Invasiveness
Invasive
This Species Brief is a concise summary of the biological, ecological, and fire‑related characteristics of an individual species derived from a Fire Effects Information System (FEIS) Species Review. Table 1 is derived from a standardized template and highlights these characteristics.
| Attribute | Characteristic | Justification | Source |
|---|---|---|---|
| Biological characteristics | |||
| Life form | Forb | Yellow starthistle is a forb. | FEIS: Botanical Description [1] |
| Typical lifespan | 0-1 year; 2-5 years | Yellow starthistle is a winter annual or sometimes biennial forb that typically completes its life cycle within a year. | FEIS: Botanical Description; Seasonal Development [1] |
| Life cycle | Annual; Biennial | Yellow starthistle is typically an annual but sometimes behaves as a biennial. In areas with mild winters, plants can behave as biennials, but mature plants rarely survive freezing winters. | FEIS: Summary; Seasonal Development [1] |
| Drought tolerance | High | Yellow starthistle is tolerant of drought and can survive at lower soil water potential than annual grasses such as medusahead. Cool, wet winters enable it to grow in winter, bolt in spring, and escape drought during hot, dry summers. | FEIS: Soils; Climate [1] |
| Rooting depth | Deep | Yellow starthistle has a taproot that can grow >1.2 m deep and has short secondary branches. Its roots grow faster and reach greater depths than associated annual grasses, and it has a deeper root system than many associated perennial grasses. | FEIS: Botanical Description; Plant Growth and Mortality [1] |
| Bark thickness at maturity | N/A | This attribute applies to trees. | FEIS [1] |
| Sheds low branches | N/A | This attribute applies to trees. | FEIS [1] |
| Reproduction and Regeneration | |||
| Adventitious buds | Root crown | Yellow starthistle may sprout from the root crown after top-kill. It can sprout after mowing and livestock grazing, but burned plants do not usually sprout. | FEIS: Vegetative Regeneration [1] |
| Time to reproductive maturity | 0-1 year | Seedlings germinate in fall or winter, overwinter as basal rosettes, bolt in late spring to early summer, and flower the following summer, completing the cycle within a year. | FEIS: Seasonal Development [1] |
| Soil seed bank longevity | Transient (<1 year); Short-term persistent (1-5 years); Long-term persistent (>5 years) | Yellow starthistle has a large, transient soil seed bank and a small, short- to long-term persistent soil seed bank. Seed longevity in the persistent seed bank ranges from about 4 years in California up to about 10 years in Washington. | FEIS: Seed Banking [1] |
| Serotinous cones | N/A | This attribute applies to conifers. Yellow starthistle seeds are achenes or cypselae that disperse after the flowers senesce. | FEIS: Botanical Description [1] |
| Seed dispersal mechanism | Gravity; Wind; Animal; Water | Plumed seeds disperse by gravity or wind after flowers senesce, whereas plumeless seeds usually remain in seedheads and fall as seedheads deteriorate. Humans, animals, and water can also transport the seeds; pappus bristles readily adhere to clothing and fur, and the pappus may aid flotation in moving water. | FEIS: Seed Dispersal [1] |
| Seed dispersal distance | Short (mostly under parent plant); Medium; Long (>1 km)* | Plumed seeds mostly fall within 0.6 m of parent plants and plumeless seeds fall just below the parent plant. Even with a combination of gusty wind and dry conditions to maximize dispersal distance, the maximum distance was 5 m. Plumed seeds adhere to clothing and fur, so long-distance spread is by animals and vehicles rather than wind, with distances not quantified. | FEIS: Seed Dispersal [1] |
| Typical requirements for seedling establishment | Bare soil; Sun | Yellow starthistle seeds germinate and seedlings establish best on moist, disturbed soils. Disturbance favors establishment by increasing bare ground, reducing vegetation, and increasing sunlight to the soil surface. | FEIS: Introductory Summary; Seedling Establishment and Mortality [1] |
| Successional Status | |||
| Shade tolerance | Shade intolerant | Yellow starthistle does not tolerate shade, grows on sites with high solar exposure, and is most competitive in high-light, disturbed environments. Plants grown under 6% full sunlight failed to flower, and the average number of flowers per plant increased with increasing sunlight. | FEIS: Shade tolerance; Seed Production and Predation [1] |
| Successional status | Early | Yellow starthistle is an early successional species that establishes best on disturbed sites, including burned areas. It does not typically occur in areas dominated by shrubs, trees, tall perennial forbs and grasses, or late-season annuals. | FEIS: Succession; Shade tolerance [1] |
| Fire | |||
| Primary fire response(s) or adaptation(s) | Recruit; Recover/Resprout* | Yellow starthistle establishes after fire from undamaged seeds in the soil seed bank or from off-site seed in newly favorable postfire conditions. It may sprout from the root crown after top-kill, but burned plants do not usually sprout and observed postfire sprouting was minimal. | FEIS: Fire Adaptations; Vegetative Regeneration [1] |
| Germination is fire stimulated | Sometimes* | Observations of increased germination and high seedling densities in burned areas suggest burning may stimulate germination of surviving seeds, with a heavy flush after fall rains following October fire. However, a seed heating experiment found that seeds were killed above about 115 to 120 °C. | FEIS: Postfire Germination [1] |
| Flowering/fruiting is fire stimulated | Sometimes* | Flowerhead production may increase after fire; plants in burned plots in northern California had more flowerheads the following summer (58 per plant) than plants in unburned plots (16 per plant). However, another study found that the difference in seedheads per plant between burned and unburned plots was not statistically significant. | FEIS: Postfire Flowerhead Production [1] |
| Season when it is most sensitive to fire | Summer | Yellow starthistle is most sensitive to fire in summer, after fuels have dried sufficiently and before it has set seed. In spring, yellow starthistle is too moist to carry fire. Some studies observed reduced germination rates after fire, but others note increased postfire seedling germination; consecutive annual summer burns can help reduce seed bank density. | FEIS: Plant Response to Fire; Fire Management Considerations [1] |
| Plant flammability | Low* | Green plants are too moist to carry fire, and dense populations may have insufficient grass fuels to carry fire; live yellow starthistle is described as nonflammable and fleshy. Once cured, dried skeletons can provide fuel for late summer wildfires, so flammability rises sharply after senescence. | FEIS: Fuels [1] |
| Early colonizer/recolonizer of burned or disturbed sites | Frequently | Yellow starthistle is an early successional species that establishes best on disturbed sites, including burned areas. Abundant seedlings often emerge with the first fall rains after fire in California grasslands, and seedling establishment and survival may exceed that on unburned sites. | FEIS: Succession; Postfire Seedling Establishment [1] |
| Effect of fire exclusion on population | Possible increase* | Yellow starthistle invasion into native perennial grasslands at Sugarloaf Ridge State Park has been attributed, in part, to fire exclusion and infrequent fire. Prescribed fire intervals mimicking historical intervals of 2 to 10 years may increase native plant diversity and control yellow starthistle. | FEIS: Fire Regimes [1] |
| Is this species typically managed with prescribed fire? | Sometimes | Most information about yellow starthistle's response to fire comes from California annual grassland studies that used prescribed fire to control invasive populations. Three or more consecutive years of prescribed fire can deplete the soil seed bank and reduce populations. However, after annual burning ceases, it may establish from the few remaining seeds in the soil seed bank or from seeds dispersed from off-site sources. | FEIS: Summary; Prescribed Fire Frequency [1] |
| Predominant historical fire frequencies of ecosystem where it most commonly occurs | Frequent; Mid-frequency* | Yellow starthistle is most invasive in annual and perennial grasslands, shrub steppes, oak savannas, and open woodlands. Grasslands and oak savannas historically burned at frequent intervals, while the sagebrush and shrub-steppe communities (where it also invades) have longer intervals. | FEIS: Fire Regimes; Plant Communities [1] |
| Predominant historical fire severity where it most commonly occurs | Frequent; Mid-frequency* | Yellow starthistle is most invasive in annual and perennial grasslands, shrub steppes, oak savannas, and open woodlands. Grasslands and oak savannas historically experienced low-severity surface fire, while the sagebrush and shrub-steppe communities (where it also invades) burn at mixed severity. | FEIS: Fire Regimes; Plant Communities [1] |
| Predominant historical fire regime group where it most commonly occurs | Insufficient information | The source document does not provide explicit information about fire regime group. It is most invasive in annual and perennial grasslands, oak savannas, and open woodlands, which typically experienced frequent low and replacement severity fires (fire regime groups 1 and 2). Sagebrush and shrub-steppe communities, where yellow starthistle is also invasive, typically experienced relatively infrequent, replacement severity fire, aligning with fire regime group 4. | FEIS: Fire Regimes [1] |
| Alters historical fuel characteristics of ecosystems where it occurs | Yes, invasive species | Yellow starthistle fuels do not carry fire as well as grass fuels, so dense populations alter fuel characteristics on invaded grassland sites and thus alter fire regime characteristics. In an eroded gully where cover was 100%, fuels were insufficient to carry a surface fire in July. | FEIS: Fire Regimes; Fuels [1] |
1. Innes, Robin J.; Zouhar, Kris. 2021. Centaurea solstitialis, yellow starthistle. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/censol
Last updated August 20, 2026