Helianthus ciliaris (Texas blueweed)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Biology and Ecology
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Plant Trade
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Social Impact
- Risk and Impact Factors
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Helianthus ciliaris DC.
Preferred Common Name
- Texas blueweed
International Common Names
- Spanish: yerba parda
- Russian: Podsolnechnik resnichatyi
Local Common Names
- USA: blueweed
- HELCI (Helianthus ciliaris)
Summary of InvasivenessTop of page H. ciliaris is a robust, deep-rooted rhizomatous perennial plant, which has shown its persistence and invasiveness in its native range as a crop weed. Although herbicides can be used effectively against it, control is still troublesome, as for any persistent rhizomatous perennial. H. ciliaris has spread accidentally to other areas in USA where it also behaves as a noxious weed, but the long-distance invasion pressure does not seem very high. H. ciliaris is certainly to be seen as a plant with a high potential to become an invasive weed in many countries around the world, if it should be accidentally introduced.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Asterales
- Family: Asteraceae
- Genus: Helianthus
- Species: Helianthus ciliaris
Notes on Taxonomy and NomenclatureTop of page Helianthus laciniatus Gray is given by some sources as a synonym, but US sources clearly indicate that this is a separate species (alkali sunflower) confined to Texas and New Mexico. Helianthus arizonensis R.C. Jackson (Arizona sunflower) is a similar but rarer plant, confined to Arizona.
DescriptionTop of page H. ciliaris is a rhizomatous, herbaceous perennial, 30-70 cm tall and its roots can reach as deep as 2 m into the soil. The stems and foliage are downy and bluish green, giving the name 'blueweed'. H. ciliaris has narrow linear or lanceolate sessile leaves, mostly opposite, 3-10 cm long, with a wavy ciliate margin. The flower heads, 2-4 cm across, have yellow ray florets and reddish disk florets; they are borne singly (or few) on numerous long axillary shoots. Plants appear as large clumps, covered with yellow flower heads, because of the numerous shoots formed from the underground rhizomes. The fruits are greyish-brown achenes, four-angled, about 3 mm long, without pappus, resembling a small sunflower seed.
Plant TypeTop of page Broadleaved
DistributionTop of page H. ciliaris is native to Texas, USA and has probably extended its range in the USA as far as California, Idaho, Nebraska and Illinois. It remains very localized in some states where it has been recorded in the northern extremes of its range (Idaho and Illinois). Other US states remain free from this weed, as does Canada. Elsewhere, H. ciliaris also occurs in northern Mexico, where it is presumably native. The native range of H. ciliaris is given as Texas, Oklahoma, New Mexico and Utah in the USA, and Chihuahas, Coahuila, Nuevo Leon, San Luis Potosi and Tamaulipas in Mexico by USDA-ARS (2003), indicating that the exact centre of origin remains uncertain. The distribution table reflects the more restricted concept of an original native range of Texas and Mexico.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Mexico||Restricted distribution||Native||Invasive||Salinas, 1981; USDA-ARS, 2003|
|-Arizona||Restricted distribution||Introduced||USDA-NRCS, 2002; USDA-ARS, 2003|
|-California||Restricted distribution||Introduced||Invasive||USDA-NRCS, 2002|
|-Idaho||Restricted distribution||Introduced||USDA-NRCS, 2002|
|-Illinois||Restricted distribution||Introduced||Invasive||USDA-NRCS, 2002|
|-Kansas||Restricted distribution||Introduced||Invasive||USDA-NRCS, 2002; USDA-ARS, 2003|
|-Nebraska||Restricted distribution||Introduced||USDA-NRCS, 2002|
|-Nevada||Restricted distribution||Introduced||USDA-NRCS, 2002|
|-New Mexico||Present||Introduced||USDA-ARS, 2003|
|-New South Wales||Restricted distribution||Introduced||Invasive||Lazarides et al., 1997|
|-Queensland||Restricted distribution||Introduced||Invasive||Lazarides et al., 1997|
History of Introduction and SpreadTop of page H. ciliaris has extended its range in the USA, and may be expected to spread further; it threatens in particular Oregon and Washington. There is no indication that this weed is spreading in Mexico or in Central America. H. ciliaris has been recorded as an alien weed in New South Wales and Queensland, Australia (Lazarides et al. 1997) but only in botanical publications. The date of introduction is not known and it does not appear to be spreading invasively in Australia. There are apparently no records in other continents, even as a casual. For example, it does not appear in lists of alien plants recorded in Austria or in the UK. According to Moskalenko (2001), it has been recorded in Sweden, but no source of this record is indicated; and it is not recorded as present in Russia though seeds have been intercepted at ports of entry.
Risk of IntroductionTop of page In view of the notoriety of H. ciliaris in the USA as a noxious weed (USDA-NRCS, 2002), it does not seem likely that it would be deliberately introduced into other countries. Since movement of soil is highly regulated in most countries, and H. ciliaris is unlikely to be found in nurseries exporting plants with growing medium, the risk of movement by this pathway seems minor at the present time. Contamination of various commodities by seeds is more likely, but seed germination is poor. No particular information appears to be available on the longevity of seeds. US states which consider H. ciliaris as a noxious weed have requirements for the special processing of feed grain from infested states. H. ciliaris has not apparently been found in Europe as a casual, despite the import of North American grain over long periods. This suggests that the risk of effective introduction is not very high. This is further borne out by the relatively slow spread of this weed in North America, in circumstances where it has had the possibility to spread over a long period. Nonetheless, H. ciliaris is certainly to be seen as a plant with a high potential to become an invasive weed in many countries around the world, if it should be accidentally introduced. H. ciliaris is regulated as a noxious weed in several states of the USA (USDA-NRCS, 2002), in Russia (Moskalenko, 2001) and in Ukraine (and probably other countries of the former USSR). It is not, however, considered to be a noxious weed in Australia though it is introduced there.
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Terrestrial ‑ Natural / Semi-natural||Riverbanks||Present, no further details||Harmful (pest or invasive)|
Hosts/Species AffectedTop of page H. ciliaris is a perennial weed whose populations can build up on the same plot of land under different successive crops. It is not particularly associated with any crop, except by the accident of its geographical distribution, such as on cotton in Texas.
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page Vegetative growing stage
Biology and EcologyTop of page Genetics
The basic chromosome number in this group is x=17. The H. ciliaris complex is made up of diploids, tetraploids and hexaploids (Jackson and Hauber, 1994), the most typical number being tetraploid (n=34). Both alloploidy and autoploidy occur. Hexaploids contain a 'B genome' which may be derived from the diploid H. laciniatus, whose range overlaps that of the tetraploid cytotype. This B genome may confer the drought tolerance necessary for the success of H. ciliaris as a weed in more arid areas. It seems conceivable that polyploidy may be associated with more invasive clones, spreading by vegetative reproduction but having poor seed set and germination, but this remains to be demonstrated.
Seeds germinate slowly and poorly; only 3% were observed to germinate over a period of 30 days (Cooley and Smith, 1973a). No particular information appears to be available on the longevity of seeds. Reproduction is mainly vegetative. The underground rhizomes form new shoot buds at intervals, which later develop into new above-ground shoots. Colonies enlarge in this way over a period of years. Small fragments of rhizome are able to survive in the soil and give rise to new plants; 10 planted rhizome sections gave rise to over 2000 plants in 19 months (Cooley and Smith, 1973b). Cutting or mowing the plants stimulates the development of new shoots from the rhizomes.
As a wild plant, H. ciliaris is adapted to the conditions of western Texas, USA. As an agricultural weed, its distribution remains clearly centred on the same location.
Soil TolerancesTop of page
Special soil tolerances
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
Notes on Natural EnemiesTop of page Trupanea bisetosa attacks the seed heads of Helianthus spp., including H. ciliaris, but this is of little practical importance since the species is mainly invasive by vegetative reproduction (Cavender and Goeden, 1982). H. ciliaris is reported to be resistant to certain insect pests of sunflower (H. annuus) such as Homoeosoma electellum (Rogers et al., 1987) and Zygospila exclamationis (Rogers and Thompson, 1978).
Means of Movement and DispersalTop of page Locally, H. ciliaris is dispersed as rhizome fragments associated with soil, possibly carried by agricultural machinery. As seed germination is slow and poor, seed dispersal is probably relatively unimportant in local spread. Over long distances, however, seeds contaminating various commodities, such as grain, may introduce the weed. Presumably, rhizome fragments may also be carried over long distances in association with any kind of movement of soil. The mode of introduction of H. ciliaris into new areas in the USA has not apparently been specifically determined. International spread has evidently occurred, since the weed has been introduced into parts of Australia (Lazarides et al., 1997).
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Growing medium accompanying plants||roots|
|True seeds (inc. grain)||seeds|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Stems (above ground)/Shoots/Trunks/Branches|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page H. ciliaris is cited as the 'worst weed in West Texas', where it affects many different crops and also occurs in non-crop situations. However, its relatively restricted distribution, and slow spread, limits its total economic impact. Smith et al. (1973) showed that yield and quality losses of cotton and grain sorghum were inversely correlated with densities of H. ciliaris. This weed has attracted only moderate attention in the scientific literature since the 1980s, but it is very well featured on websites in Texas, USA, where it continues to present problems of control, and in US states which list it as a noxious weed.
Environmental ImpactTop of page H. ciliaris appears to be invasive mainly on cultivated land, or in wastelands or other marginal situations. It does not appear to invade natural environments.
Impact: BiodiversityTop of page The existence of polyploid clones of H. ciliaris, including hexaploids probably including genetic material from the related H. laciniatus, suggests that agriculture has possibly favoured the spread of new clones of this species, increasing its biodiversity, conceivably at the expense of other species. However, this impact on biodiversity is no greater than that of the agriculture which favours it in the first place.
Social ImpactTop of page No social impacts are evident.
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Has high reproductive potential
- Negatively impacts agriculture
- Competition - monopolizing resources
- Difficult/costly to control
UsesTop of page H. ciliaris has no uses.
Similarities to Other Species/ConditionsTop of page H. laciniatus is a similar non-weedy species, which has probably contributed its genome to hexaploid clones of H. ciliaris which are more drought-tolerant.
Prevention and ControlTop of page H. ciliaris is a deep-rooted rhizomatous perennial weed, difficult to control by cultural or mechanical methods. Due to the ease with which small rhizome fragments can give rise to new plants, mechanical control methods may make the problem worse. Various herbicides applied to stands of H. ciliaris give effective control, e.g. glyphosate (Salinas, 1981), especially with a wetting agent (Chykaliuk et al., 1980), dicamba (Keeling and Abernathy, 1988) and imizapyr.
Because H. ciliaris has a restricted distribution in North America, its exclusion is an important concern. H. ciliaris is rated as a restricted noxious weed in Arizona, and features on an 'A list' of noxious weeds in California, Oregon and Washington. Spread by vegetative reproduction is localized and slow, so control by surveillance and eradication can be envisaged. The weed appears to be contained at the present time.
No biological control agents have been proposed for H. ciliaris.
ReferencesTop of page
Chykaliuk PB; Abernathy JR; Gipson JR, 1980. Effect of additives on herbicide uptake and control of Texas blueweed, woolyleaf bursage and silverleaf nightshade. Proceedings of the 33rd Annual Meeting of the Southern Weed Science Society., 236
Coggon D, 1999. Written findings of the State Noxious Weed Control Board - Texas blueweed (Helianthus ciliaris DC).
Cooley AW; Smith DT, 1973. Seed germination of woolly leaf bursage, Texas blueweed and groundcherry. Consolidated Progress Report, Texas Agricultural Experiment Station, Nos.PR 3197-3209: Weed and herbicide research in W:3-6
Lazarides M; Cowley K; Hohnen P, 1997. CSIRO Handbook of Australian Weeds. Collingwood, Australia: CSIRO.
Moskalenko GP, 2001. Quarantine Weeds for Russia. Moscow, Russia: Plant Quarantine Inspectorate.
Rogers CE; Gershenzon J; Ohno N; Mabry TJ; Stipanovic RD; Kreitner GL, 1987. Terpenes of wild sunflowers (Helianthus): an effective mechanism against seed predation by larvae of the sunflower moth, Homoeosoma electellum (Lepidoptera: Pyralidae). Environmental Entomology, 16(3):586-592
Salinas GF, 1981. Control of Helianthus ciliaris with glyphosate in walnuts and vines in northern Mexico. Memorias II Congresso nacional de la ciencia de la maleza. Sociedad Mexicana de la Sciencia de la Maleza, Chapingo.
USDA-ARS, 2003. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx
USDA-NRCS, 2002. The PLANTS Database, Version 3.5. National Plant Data Center, Baton Rouge, USA. http://plants.usda.gov.
Distribution MapsTop of page
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