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Xerochrysum bracteatum
Xerochrysum bracteatum
Xerochrysum bracteatum
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Xerochrysum bracteatum
Wild form of Xerochrysum bracteatum
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Genus: Xerochrysum
Species:
X. bracteatum
Binomial name
Xerochrysum bracteatum
(Vent.) Tzvelev
Synonyms

Bracteantha bracteata (Vent.) Anderb. & Haegi
Helichrysum bracteatum (Vent.) Andrews
Helichrysum lucidum Henckel[1][2]
Helichrysum chrysanthum Pers.[2][3]

Xerochrysum bracteatum, commonly known as the golden everlasting or strawflower, is a flowering plant in the family Asteraceae native to Australia. Described by Étienne Pierre Ventenat in 1803, it was known as Helichrysum bracteatum for many years before being transferred to a new genus Xerochrysum in 1990. It is an annual[4] up to 1 m (3.3 ft) tall with green or grey leafy foliage. Golden yellow or white flower heads are produced from spring to autumn; their distinctive feature is the papery bracts that resemble petals. The species is widespread, growing in a variety of habitats across the country, from rainforest margins to deserts and subalpine areas. The golden everlasting serves as food for various larvae of lepidopterans (butterflies and moths), and adult butterflies, hoverflies, native bees, small beetles, and grasshoppers visit the flower heads.

The golden everlasting has proven very adaptable to cultivation. It was propagated and developed in Germany in the 1850s, and annual cultivars in a host of colour forms from white to bronze to purple flowers became available. Many of these are still sold in mixed seed packs. In Australia, many cultivars are perennial shrubs, which have become popular garden plants. Sturdier, long-stemmed forms are used commercially in the cut flower industry.

Taxonomy

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French botanist Étienne Pierre Ventenat described the golden everlasting as Xeranthemum bracteatum in his 1803 work Jardin de Malmaison,[5] a book commissioned by Napoleon's first wife Joséphine de Beauharnais to catalogue rare plants that she had collected and grown at the Château de Malmaison.[6] The Latin species name bracteatum refers to the papery bracts (often mistakenly called petals) of the flower heads.[7] Henry Cranke Andrews transferred it to the genus Helichrysum based on the morphology of its receptacle in 1805,[8] and it was known as Helichrysum bracteatum for many years. Leo Henckel von Donnersmarck described it as Helichrysum lucidum in 1806, and Christiaan Hendrik Persoon as Helichrysum chrysanthum in 1807.[2] It was given the name Bracteantha bracteata in 1991,[9] when Arne Anderberg and Laurie Haegi placed the members that are known as strawflowers of the large genus Helichrysum into a new genus Bracteantha, and designated B. bracteata as the type species.[10] However, they were unaware that Russian botanist Nikolai Tzvelev had already placed X. bracteatum in the new, and at the time monotypic, genus Xerochrysum the previous year.[11] This name was derived from the Greek words xeros "dry", and chrysum "golden", likely relating to the nature of the distinctive bracts.[12] Confusion existed for a decade, with Bracteantha appearing in literature and the horticultural trade until it was clarified in 2002 that the latter name took precedence.[10] Strawflower is the popular name for X. bracteatum in Europe, while in Australia it is known as an everlasting or paper daisy.[7] An alternate name in 19th-century Europe was immortelle.[13] X. bracteatum itself is very variable and may represent several cryptic species.[10] Alternately, the Tasmanian species Xerochrysum bicolor may be combined with it in future taxonomic revisions.[14]

Xerochrysum bracteatum and its relatives belong to the Gnaphalieae or paper daisies, a large tribe within the daisy family, Asteraceae. However, a 2002 molecular study of the Gnaphalieae has indicated the genus Xerochrysum is probably polyphyletic, as the two species sampled, X. bracteatum and X. viscosum, were not closely related to each other.[15] X. bracteatum has been recorded hybridising with X. viscosum and X. papillosum in cultivation, and possibly also Coronidium elatum and C. boormanii.[16]

Description

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Wild form showing yellow bracts and orange central disc

The plant is an erect perennial, or occasionally annual, herb that is simple or rarely branched at its base. It generally reaches 20 to 80 cm (8 to 31.5 in) in height, but can have a prostrate habit in exposed areas such as coastal cliffs. The green stems are rough and covered with fine hairs, and are robust compared with those of other members of the genus. The leaves are lanceolate, elliptic, or oblanceolate in shape and measure 1.5 to 10 cm (0.59 to 3.94 in) long and from 0.5 to 2 cm (0.20 to 0.79 in) wide. They are also covered with cobwebby hairs. Sitting atop tall stems above the foliage, the flower heads range from 3 to 7 cm (1 to 3 in) in diameter. Occasionally, multiple heads arise from the one stem.[14] Like the flowers of all Asteraceae, they are composed of a central disc which contains a number of tiny individual flowers, known as florets; these sit directly on an enlarged part of the stem known as the receptacle.

Around the disc is an involucre of modified leaves, the bracts, which in Xerochrysum, as in most Gnaphalieae, are petal-like, stiff, and papery. Arranged in rows, these bracts curl over and enclose the florets, shielding them before flowering.[17] They create the impression of a shiny and yellow corolla around the disc. The intermediate bracts are sometimes white, while the outer ones are paler and often streaked reddish or brown (a greater variety of colours are found in cultivars).[18] These bracts are papery and dry, or 'scarious', with a low water content, unlike leaves or flower parts of other plants. They are made up of dead cells, which are unusual in that they have a thin primary and a thick secondary cell wall, a feature only found in sclerenchyma, or structural, cells, not cells of flowers or leaves.[19]

The individual florets are yellow.[18] Those on the outer regions of the disc are female, while those in the centre are bisexual. Female flowers lack stamens and have only a very short, tube-shaped corolla surrounding a pistil that splits to form two stigmas, while bisexual or hermaphrodite flowers have a longer corolla, and (as in virtually all members of the family) five stamens fused at the anthers, with the pistil emerging from the center. The yellow corolla and pistil are located above an ovary with a single ovule, and surrounded by the pappus, the highly modified calyx of Asteraceae. It comprises a number of bristles radiating around the florets.[20] Yellow in colour, they persist and are thought to aid in the wind dispersal of the 0.3 cm (0.12 in) long fruit.[21] The smooth brown fruit, known as a cypsela, is 2 to 3 mm long with the pappus radiating from one end.[22]

In the wild, X. bracteatum can be distinguished from X. bicolor in Tasmania by its broader leaves and cobwebby hairs on the stems, and from X. macranthum in Western Australia by the flower head colour; the latter species has white flower heads whereas those of X. bracteatum are golden yellow. Xerochrysum subundulatum from alpine and subalpine areas of New South Wales, Victoria, and Tasmania is rhizomatous, and has markedly pointed orange bracts.[22] The eastern Australian species X. viscosum may be distinguished by its rough and sticky leaves.[23]

The plant is a source of helenynolic acid, a rare fatty acid.

Distribution and habitat

[edit]
Xerochrysum bracteatum near Weethalle

Xerochrysum bracteatum occurs in all Australian mainland states and territories, as well as Tasmania.[18] Widespread, it is found from North Queensland across to Western Australia, and in all habitats excluding densely shaded areas.[7] It grows as an annual in patches of red sand in Central Australia,[24] responding rapidly to bouts of rainfall to complete its lifecycle.[25] It is common among granite outcrops in southwest Western Australia,[13] and is found on heavier and more fertile soils in the Sydney region, such as basalt-, shale-, or limestone-based soils, generally in areas with a high water table.[26] Associated species in the Sydney Basin include blackbutt (Eucalyptus pilularis) in open forest, and the shrubs Empodisma minus and Baloskion australe in swampy areas.[26] It has been reported growing in disturbed soil, along roadsides and in fields in the New England region in the United States.[27]

Xerochrysum bracteatum Everlasting flower from Ooty, India

Ecology

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The brightly coloured bracts act as petals to attract insects such as hoverflies, native bees, and small beetles that pollinate the florets.[17] Grasshoppers also visit the flower heads.[28] The caterpillars of Tebenna micalis have been recorded on this species, as have those of the Australian painted lady (Vanessa kershawi).[29] The tiny fruits are dispersed by wind, and germinate and grow after fire or on disturbed ground.[26]

Flower production is related to increasing day length, and in general, plants produced the most flowers from December to March. Varying planting times or artificially changing light levels might be ways to increase production of flowers outside these months.[30]

The water mould (oomycete) Bremia lactucae has infected commercial crops in Italy and California. In 2002 on the Ligurian coast, widespread infection of several cultivars, most severely 'Florabella Pink' and to a lesser extent 'Florabella Gold' and 'Florabella White', resulted in leaf blistering and the development of chlorotic lesions on the leaves, and white patches on the undersides, particularly in areas of poor ventilation.[31] There was an outbreak of downy mildew in a cultivated crop of Xerochrysum bracteatum in San Mateo County, California in 2006, in which the leaves developed large chlorotic lesions.[32] A Phytoplasma infection damaged X. bracteatum crops in the Czech Republic between 1994 and 2001, causing poor growth, bronzing of foliage, and malformation of flower heads. Genetically, the pathogen was indistinguishable from the agent of aster yellows.[33] The root-knot nematode (Meloidogyne incognita) attacks and forms galls on the roots, which leads to the morbidity or death of the plant.[26]

Cultivation

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A European colour form

Xerochrysum bracteatum had been introduced to cultivation in England by 1791.[34] German horticulturist Herren Ebritsch obtained material and developed it at his nursery in Arnstadt near Erfurt in Germany. He bred and sold cultivars of many colours from bronze to white to purple, which spread across Europe in the 1850s. The bracts of these early forms tended to remain cupped around the flower head rather than flatten out like the native Australian forms.[7] These were also annual rather than perennial forms. Many were given cultivar names such as 'atrococcineum' (dark scarlet flower heads), 'atrosanguineum' (dark blood-red flower heads), 'aureum' (golden yellow flower heads), 'bicolor' (red-tipped yellow flower heads), 'compositum' (large multicoloured flower heads), 'macranthum' (large rose-edged white flower heads), and 'monstrosum' (flower heads with many bracts), although today they are generally sold in mixed seed for growing as annuals.[35] Some coloured forms of South African Helichrysum are thought to have been introduced to the breeding program, which resulted in the huge array of colours. X. bracteatum was one of several species that became popular with European royalty and nobility from the early 19th century, yet were little noticed in Australia until the 1860s, when they became more prominent in Australian gardens.[34]

An orange-red-flowered cultivar

Most of the cultivars brought into cultivation in Australia in the latter part of the 20th century are perennials.[36] 'Dargan Hill Monarch' was the first of these, and many more have followed.[35] Profusely flowering, these grow in many colours including white, yellow, orange, bronze, pink, and red. Their commercial lifespans are generally around three years.[37] Queensland-based company Aussie Winners has a range of compact plants ranging from orange to white known as Sundaze.[38] Plants of this series usually have larger leaves.[39] This range won the Gran premio d'oro at the Euroflora exposition in Geneva in 2001, for the best new plant series in the previous three years. 'Florabella Gold', a member of the Florabella series, won the award for best new pot plant (vegetative) in the Society of American Florists' competition of 1999.[37] The Wallaby cultivars are range of taller forms with narrow leaves and white, yellow or pink flowers.[40] Other commercial ranges include the Nullarbor series, and Queensland Federation daisies, including 'Wanetta Sunshine' and 'Golden Nuggets'.[37]

Xerochrysum bracteatum is easy to grow both from seeds and from cuttings, although named cultivars only grow true from cuttings. Plants benefit from pruning of old growth in winter to allow for new growth in spring. Dead-heading, or pruning off old flower heads, promotes the production of more flowers.[7] Fresh seeds germinate in 3 to 20 days and require no special treatment.[14] Plants grow best in acid, well-aerated soils of pH 5.5 to 6.3, with low levels of phosphorus. They are sensitive to iron deficiency, which presents as yellowing (chlorosis) of the youngest leaves while the leaf veins remain green.[41]

Xerochrysum bracteatum can be grown in large pots or window boxes, and is a good pioneer plant in the garden until other plants become more established. Lower-growing cultivars are suitable for hanging baskets and border plantings.[40] The flowers attract butterflies to the garden.[42] Dried flowers are long lasting—up to some years—and are used in floral arrangements and the cut flower industry.[39] More robust longer stemmed forms are used for commercial cut flowers.[43] The main factor limiting lifespan of dried flowers is the wilting of stems, so flowers are sometimes wired into arrangements. Immersing flowers in glycerol or polyethylene glycol also lengthens lifespan.[44]

Cultivars

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'Dargan Hill Monarch'
  • 'Dargan Hill Monarch' was a natural form collected around 1.6 km (0.99 mi) inland from Cunninghams Gap in southern Queensland in May 1961, and registered in February 1977. It is a low perennial shrub 60 to 80 cm (23.5 to 31.5 in) high and 1.5 m (4.9 ft) across. The foliage is grey and the large flowers are 7–9 cm in diameter and golden yellow in colour.[47] It grows best in full sun and fair drainage. Cuttings strike readily, as does seed, although seedlings may differ from the parent.[36]
  • 'Cockatoo' arose as a spontaneous hybrid between 'Dargan Hill Monarch' and a white-flowered perennial form of X. bracteatum, in the garden of Victorian plantsman Doug McKenzie in Ocean Grove near Geelong in Victoria. He applied to the Australian Cultivar Registration Authority (ACRA) for registration, which was granted in 1980. It is a dense perennial shrub which reaches around 1 m (3.3 ft) high and wide. The oblanceolate leaves measure 6 to 12 cm (2.5 to 4.5 in) long and are covered with fine hairs that give them a greyish cast. Fine hairs also cover the stems. The flower heads have light lemon-yellow bracts and orange discs and average 7 cm (3 in) in diameter. They are held on long stems around 12–15 cm (4.5–6 in) above the foliage. Like all forms, it prefers full sun. Although a perennial, it loses vigour after a few years, at which time it is best replaced. The name 'Cockatoo' was chosen as the shape and colour of the ray florets are reminiscent of the wing feathers of the sulphur-crested cockatoo.[48]
  • 'Golden Bowerbird' is a hybrid, bred by a deliberate backcross of 'Cockatoo' to 'Dargan Hill Monarch' by Doug McKenzie, who applied for registration with the ACRA in 1980. (It was granted in 1981.) It has much larger flower heads than both parents, yet is a smaller shrub, which reaches 40 cm (15.5 in) high by 70 cm (27.5 in) wide. Denser than that of other forms, the foliage is covered in fine grey hair. On stalks around 10 cm (4 in) above the foliage, the flower heads measure up to 9 cm (3.5 in) in diameter, although larger ones up to 10 cm are occasionally seen. They have around 300 bracts per flower head, compared with 80 for 'Dargan Hill Monarch' and 200 in 'Cockatoo', giving them a "doubled" look.[49] It is reported as producing fewer flower heads than 'Princess of Wales'.[50]
  • 'Princess of Wales' is a spontaneous hybrid, arising from a cross between 'Dargan Hill Monarch' and an annual form. Arising in the Australian National Botanic Gardens in Canberra, it was selected by employee Peter Ollerenshaw in summer 1983. He applied to register the cultivar with ACRA in March 1985.[51] It was named in honour of a visit by Diana, Princess of Wales to the gardens in November 1985,[7] the same month registration was granted.[51] With compact foliage, this form reaches 60 cm (23.5 in) high and wide. Unlike its parent 'Dargan Hill Monarch', its foliage has hair only on the midrib on the leaf underside.[51] It flowers very profusely,[50] and the large flower heads are borne on stalks 5–9 cm (2–3.5 in) above the foliage. Unlike other forms, the stems wither and die naturally after flowering, making way for more new growth and flowers.[51] The flower heads are golden yellow and measure 6 cm (2.5 in) across.[7]
  • 'Diamond Head' was a natural form collected around Diamond Head in New South Wales, where it is quite common on bluffs and cliffs. John Wrigley, curator of the Australian National Botanic Gardens at the time, applied to the ACRA to have it registered, which it was in February 1977.[7] Found on an exposed headland in nature, it grows as a low mat-like perennial shrub 8 cm (3 in) high and 60 cm (2.0 ft) across. The foliage is green and rough and the flowers are 3 cm in diameter and yellow in colour with an orange disc.[52] It makes an ideal plant for rockeries, and strikes easily from cuttings during the spring growing period.[53]
Colour forms in cultivation 'Strawburst Yellow', centre, 'Kimberley Sunset' (cream) bottom left, small bronze-flowered form 'Sundaze Dazette Mambo' (far right)
  • 'Hastings Gold' was a natural form from Hastings Point to the east of Murwillumbah on the New South Wales far north coast. It is a perennial herb with green bushy foliage reaching 25 cm (10 in) high and 70 cm (27.5 in) wide. The golden yellow flower heads measure 5 cm (2 in) across and are held on stalks 20 cm (8 in) above the foliage. It is smaller than the similarly coloured 'Dargan Hill Monarch' and larger than 'Diamond Head'.[54]
  • 'Nullarbor Flame' was a selection introduced into cultivation in 1997 that produces abundant red flowers with yellow discs and a diameter of 4.5 cm (1.8 in). The plant grows to 50–70 cm (19.5–27.5 in) tall and 50–80 cm (19.5–31.5 in) wide.[55]
  • 'Pink Sunrise' was developed by Goldup Nurseries in Victoria in 1986, of unknown origin, presumably a hybrid. It is a compact perennial that reaches 30 cm (12 in) high and 60 cm (23.5 in) wide. The flower heads are pink in bud, before opening as cream with orange discs.[56]
  • 'White Monarch' was a spontaneous garden hybrid that resembles 'Dargan Hill Monarch' but with white flower heads with orange discs measuring up to 8 cm (3 in) in diameter.[57]
  • 'Lemon Monarch' resembles 'Cockatoo', but its lemon-coloured flower heads have fewer bracts.[50] It has bushy foliage.[58]
  • 'Strawburst Yellow', patented as 'Stabur Yel', is a form with large bright yellow flower heads averaging around 6.3 cm (2.5 in) in diameter. The result of a planned breeding program in Gilroy, California, it was bred by Jason Jandrew of Goldsmith Seeds from a lemon yellow-flowered form crossed with a yellow-flowered form in 2005. The pollination occurred in May, the resultant seed was sown in September, and what was to become the clone was chosen in December for its large flower size, colour and compact foliage.[59]
  • 'Lemon Princess' is thought to be a hybrid between X. bracteatum and X. viscosum.[60]

References

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Further reading

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[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Xerochrysum bracteatum

View on Grokipedia
from Grokipedia
Xerochrysum bracteatum, commonly known as the strawflower, golden everlasting, or paper daisy, is a of in the native to . It is an annual or short-lived that typically grows 20–80 cm (8–32 in) tall, though it can reach up to 1 m in shrubby forms or adopt a prostrate in exposed coastal areas. The plant features erect, rough, green stems bearing alternate, lance-shaped, gray-green leaves up to 10 cm long, and solitary terminal flower heads 2–7 cm in diameter resembling daisies, with a central cluster of small yellow disk florets surrounded by overlapping, colorful, papery bracts in shades of yellow, orange, red, pink, or white that retain their vivid color and shape when dried, making them popular for everlasting floral arrangements. Native to all Australian states and territories, Xerochrysum bracteatum is widespread in diverse habitats including open grasslands, woodlands, shrublands, and disturbed sites such as post-fire areas or roadsides, thriving in full sun and well-drained soils across arid, semi-arid, temperate, subalpine, and subtropical climates, but avoiding densely shaded environments. The species exhibits variability in form, from low-growing annuals to more robust perennials, and is moderately frost-resistant in many populations. It has become naturalized in some regions outside , such as parts of the , through ornamental cultivation. Formerly classified under genera such as or Bracteantha, Xerochrysum bracteatum is valued globally as a low-maintenance , blooming from spring to autumn in USDA zones 8–10 when grown as a , or as an in cooler climates. Numerous cultivars, such as 'Diamond Head' (compact yellow-flowered) and 'Kimberley Sunset' (tall pink-flowered), have been bred for garden borders, containers, rockeries, and cut-flower production, prized for their and ability to provide long-lasting color in fresh bouquets or dried crafts. The plant supports pollinators with its nectar-rich flowers.

Taxonomy and classification

Etymology and synonyms

The genus name Xerochrysum is derived from the Greek words xeros, meaning "dry," and chrysos, meaning "gold," alluding to the dry, papery, golden-yellow bracts that characterize the genus. The species epithet bracteatum comes from the Latin bracteatus, meaning "bearing bracts," in reference to the prominent, colorful bracts surrounding the flower heads. Common names for Xerochrysum bracteatum include golden everlasting, strawflower, paper daisy, and immortelle, reflecting its durable, papery flowers used in dried arrangements; regional variations such as Australian everlasting or yellow paper daisy are also used, particularly in its native . The species was first described as Xeranthemum bracteatum by Étienne Pierre Ventenat in 1803, based on a cultivated specimen in the Jardin de . It was subsequently transferred to Helichrysum bracteatum (Vent.) Willd. in 1809 and remained under that name for nearly two centuries until reclassified as Xerochrysum bracteatum (Vent.) Tzvelev in 1990. Accepted synonyms, according to the Australian Plant Name Index (APNI), include Bracteantha bracteata (Vent.) Anderb. & Haegi, chrysanthum Pers., and Xeranthemum bracteatum Vent., among others.

Phylogenetic relationships and recent revisions

Xerochrysum bracteatum is placed within the family Asteraceae and tribe Gnaphalieae, with close relatives including the genera Coronidium and Ozothamnus, based on shared morphological and molecular traits such as pappus structure and inflorescence characteristics. The species was originally described as Helichrysum bracteatum but transferred to the newly established genus Xerochrysum by Nikolai Tzvelev in 1990, primarily due to differences in bract coloration, pappus persistence, and cypsela morphology that distinguished it from core Helichrysum species. A 2002 molecular phylogenetic study using chloroplast (trnL , trnL/F spacer, rbcL) and nuclear (ITS) sequences revealed within Helichrysum, supporting the separation of Australian taxa like Xerochrysum into distinct genera to reflect monophyletic groups within Gnaphalieae. Recent revisions, detailed in a 2022 study by Collins et al. in Australian Systematic Botany, integrated morphological analyses with molecular data from ITS and ETS ribosomal regions, as well as genome-wide SNPs via DArTseq, to delimit species boundaries in the X. bracteatum complex; this work recognized 11 new species (e.g., X. andrewiae, X. strictum) and reinstated X. banksii, while indicating that the broad X. bracteatum encompasses cryptic diversity, potentially warranting splits into highland and lowland forms based on genetic clustering and subtle trait variations.

Description

Morphology

Xerochrysum bracteatum is an erect, or short-lived typically growing 20–100 cm tall, though it can reach up to 1.8 m in favorable conditions, with branching stems that are often covered in white woolly or cobwebby hairs and may become viscid due to glandular secretions. The stems are finely sulcate and bear alternate leaves that are lanceolate to oblanceolate or elliptic, measuring 2–10 cm long and 0.5–2.5 cm wide, with sessile or clasping bases, entire to slightly toothed margins, and surfaces that range from green to grey-green, often hispidulous on the adaxial side and cottony or glandular on the abaxial side. The inflorescences consist of solitary or clustered capitula, or flower heads, that are 3–6 cm in diameter and borne on peduncles up to 30 cm long, often subtended by 3–10 foliaceous bracts. The involucral bracts, arranged in 5–7 overlapping series, are papery and rigid, resembling petals in their colorful display of yellow, orange, red, or white hues, with outer bracts broadly ovate and inner ones acute to acuminate; these bracts provide the diagnostic feature reflected in the species epithet "bracteatum." Within each head, there are 100–200 central disk florets that are tubular and bright yellow, while outer ray florets are absent or reduced to sterile, narrowly tubular forms with 4 lobes; the florets are complemented by a pappus of bristles attached to the cypselae for seed dispersal. The is taprooted, supporting the plant's to well-drained, often sandy soils in its native habitats. Variations in morphology are notable, with annual forms generally shorter at 20–40 cm and more compact, while variants can exceed 1 m in height; wild populations also exhibit bract color polymorphism, ranging from predominantly yellow or white to rarer shades in some populations, alongside differences in hair density and size across geographic ranges.

Life cycle and reproduction

Xerochrysum bracteatum displays flexible life forms influenced by conditions. In arid environments, it grows as an annual, completing its entire life cycle within a single growing season following rainfall events. In contrast, moister habitats allow it to persist as a short-lived , potentially living 3–5 years and regrowing from woody rootstocks. Germination typically occurs in spring after autumn or winter rains, with seeds requiring exposure to for successful sprouting. Optimal temperatures range from 18–25°C, yielding rates of 7–10 days under suitable conditions. Flowering is initiated in summer and continues through autumn, from to in its native Australian range, in response to increasing day lengths and warming temperatures. A single plant may produce numerous flower heads—often dozens to hundreds—over the blooming period, each consisting of many disk florets. Reproduction is predominantly sexual, occurring via florets that are pollinated by and develop into achenes measuring 2–3 mm long, topped with a pappus of fine bristles. The is self-compatible, enabling seed set without cross-pollination, though predominates in natural populations. Each flower head can yield up to 100 achenes, with high initial viability rates of 85–100% observed in collections. lack dormancy and remain viable for several years, their longevity enhanced by dispersal mechanisms that protect them from environmental stress. The papery bracts of the involucre provide additional safeguarding for developing achenes. In annual populations, the plant senesces and dies back after seed maturation and dispersal at the end of the season. individuals, however, survive winter and regrow from basal crowns in the following spring.

Distribution and habitat

Geographic range

Xerochrysum bracteatum is native to , where it exhibits a broad distribution across the mainland, occurring in all states and territories, including , , Victoria, , , , and the . The species ranges from to subalpine elevations, thriving in open habitats from coastal regions to inland areas up to approximately 2000 m. It is particularly abundant in the southeastern states, including (from the and Blue Mountains southward), Victoria, and , where it forms extensive populations in suitable open areas. In contrast, it is rarer in and , with scattered occurrences in the former's southern regions and the latter's southwestern outcrops and coastal zones. The species is widespread across much of the Australian continent, with notable gaps in the extreme tropical north and the most arid interior where conditions are unsuitable. Historical records indicate that X. bracteatum was first collected in the 1790s near , marking one of the earliest documented Australian native plants, with its distribution becoming more fully recognized following European settlement and subsequent botanical explorations. Beyond its native range, X. bracteatum has been introduced as an to several regions, including , where it is naturalized, and parts of the (such as and states like and ) and (e.g., ). It has naturalized in some Mediterranean climates, such as , but remains generally non-weedy with limited invasive potential, occasionally appearing in disturbed grasslands without widespread ecological disruption.

Environmental preferences

_Xerochrysum bracteatum thrives in temperate to subtropical climates across , tolerating a broad range of conditions including annual rainfall from 500 to 1400 mm and dry seasons lasting 4 to 7 months. It exhibits moderate frost tolerance down to approximately -5°C in its southern and subalpine populations, while also enduring periods through its resilient . The species prefers full sun exposure, avoiding shaded environments that limit its growth. In terms of soil, Xerochrysum bracteatum favors well-drained substrates such as sands, loams, or gravels, which prevent waterlogging and support its root development. It tolerates a range of 5.5 to 7.0, with an optimal slightly acidic to neutral profile around 5.5 to 6.5, and performs well in low-fertility conditions without requiring nutrient-rich media. The plant occupies diverse habitats including open woodlands, grasslands, heathlands, and disturbed areas like roadsides, extending from coastal dunes to subalpine meadows. It is particularly adapted to fire-prone communities, where periodic burns promote regeneration in these ecosystems. Xerochrysum bracteatum commonly co-occurs with species in woodlands and in shrublands, as well as other like Leucochrysum in settings, while shunning waterlogged or densely shaded locales. Its woolly indumentum of cottony hairs on stems and leaves helps reduce rates, aiding survival in arid conditions.

Ecology

Pollination and seed dispersal

Xerochrysum bracteatum is primarily pollinated by insects in its native Australian habitats, with native bees playing a key role in pollen transfer. Species such as Leioproctus helichrysi from the family Colletidae have been documented visiting the flowers, collecting pollen and nectar while facilitating cross-pollination. Other insects, including flies and butterflies, also contribute to pollination, drawn to the bright, papery bracts surrounding the composite flower heads that mimic petals for attraction. The diurnal opening of florets aligns with the active foraging periods of these pollinators, promoting effective pollen exchange during daylight hours. Pollen grains of X. bracteatum are characteristically and viscous, enabling them to adhere to the bodies of visiting for transport between . This sticky quality is typical of Asteraceae adapted for , enhancing rates. The plant's breeding system supports a mix of self- and cross-, though vectors favor the latter, contributing to across populations. Flowering , spanning late winter to early summer (August to February in ), synchronizes with peak activity, ensuring reliable opportunities. Seed dispersal in X. bracteatum occurs mainly through anemochory, where lightweight achenes equipped with a pappus of fine bristles act as parachutes, allowing to carry them from the parent plant. This mechanism supports the ' wide distribution in open grasslands and disturbed areas, with the persistent capitula releasing seeds post-anthesis. Dispersal is further aided occasionally by water flow or attachment to animals, though remains dominant. Peak seed release follows the flowering period, coinciding with autumn that enhance long-distance spread and colonization of new sites.

Biotic interactions and threats

Xerochrysum bracteatum engages in various biotic interactions that influence its survival and growth in native Australian ecosystems. It forms vesicular-arbuscular (VA) mycorrhizal associations, which facilitate nutrient uptake, particularly , in nutrient-poor soils typical of its habitats. These symbiotic relationships with arbuscular mycorrhizal fungi enhance the plant's ability to thrive in sandy or rocky substrates where is low. In mixed communities, such as those with nitrogen-fixing species, X. bracteatum benefits indirectly from improved levels through proximity to these leguminous neighbors. The plant is susceptible to several pathogens that can impact its health, especially under favorable conditions for disease development. , caused by Bremia lactucae, affects field-grown plants, producing irregular chlorotic lesions on leaves up to 6 cm in size, followed by gray-brown and white sporulation on the abaxial surface; symptoms appear 14 days after inoculation in pathogenicity tests conducted at 18–24°C. Root and basal rot, often induced by like spp. or spp., leads to rotted, black or brown roots and collapsed stems, particularly in poorly drained conditions. In wetter environments, rust fungi and other foliar pathogens can further compromise populations by causing leaf spots and reduced vigor. Herbivory represents another key biotic pressure, with X. bracteatum serving as a host for foraging on developing flowerheads, though these interactions do not consistently provide protection against other herbivores. Larger herbivores, such as , may browse the in overgrazed areas, contributing to stress in disturbed grasslands. Major threats to X. bracteatum include habitat loss due to and , which fragment its preferred open woodlands and grasslands, leading to local declines despite its overall widespread distribution. exacerbates these pressures through altered rainfall patterns; while the species' may allow spread in drier conditions, increased could intensify in some regions. regimes also pose risks—populations regenerate post-fire primarily via seed germination on disturbed ground, but intense or frequent burns can reduce establishment and overall abundance in fire-prone ecosystems. A 2025 continental-scale study highlights how frequency influences post-fire reproduction strategies in herbaceous , underscoring the importance of balanced fire intervals for persistence. Conservation assessments classify X. bracteatum as Least Concern across its range, reflecting its broad distribution from arid interiors to coastal areas in all Australian states and territories. However, fragmented habitats experience local declines, with 2022 molecular analyses revealing significant and reduced diversity in isolated populations, such as those in the Tablelands and Barrington Tops, due to limited (F_ST > 0.4). These findings emphasize the need for monitoring to preserve in peripheral or disjunct stands.

Cultivation and uses

History and propagation

Xerochrysum bracteatum was first collected in Australia during Captain James Cook's voyage in 1770 by botanists Joseph Banks and Daniel Solander at sites including Botany Bay, Thirsty Sound, and the Endeavour River. It is regarded as the first Australian native plant to enter cultivation, with specimens introduced to England by 1791. By the early 19th century, the plant had gained popularity among European naturalists and horticulturists, including cultivation in Empress Josephine's garden at La Malmaison in 1803. In the 1850s, German horticulturist Herren Ebritsch further developed the species at his nursery in Arnstadt near Erfurt, breeding variants for cut flower production. During the , Xerochrysum bracteatum became widely cultivated in for its papery bracts that retain color when dried, enabling use in long-lasting arrangements and mass decorative displays. Commercial breeding efforts in and expanded by the early 1900s, producing annual forms in diverse colors such as yellow, red, purple, and orange to meet demand for ornamental and dried floral products. Propagation of Xerochrysum bracteatum primarily occurs through or cuttings. Seeds are surface-sown on moist without covering, as aids , which typically takes 10-20 days at temperatures of 20-25°C. Stem cuttings from semi-ripe growth root readily in 2-3 weeks under or in a well-drained medium, while forms can be divided at the crown during . Since the , advancements in production have supported global , with high-quality stocks distributed for both ornamental and dried uses. techniques have been explored to produce disease-free plants, enhancing efficiency for commercial growers. In , Xerochrysum bracteatum played a significant role in the native plant movement following the , promoting cultivation of indigenous amid growing environmental awareness. It remains a key export in the dried flower industry, contributing to markets valued at around $20-25 million annually by the late , primarily for crafts and arrangements.

Growing conditions and care

Xerochrysum bracteatum thrives in full sun, receiving at least six hours of direct sunlight daily to promote abundant blooming and sturdy growth. should be spaced 30-45 cm apart to ensure adequate air circulation and prevent overcrowding, which can lead to issues. It performs as a in USDA hardiness zones 8-11, where mild winters allow overwintering, but is typically grown as an in cooler regions. The plant prefers well-drained sandy with a range of 5.5-6.5 to mimic its native Australian adaptations to arid environments. Once established, it exhibits moderate , requiring weekly watering of about 2.5 cm during dry periods to maintain vigor without causing . Overhead watering should be avoided to minimize the risk of foliar diseases like in humid conditions. Fertilization needs are low, as the plant grows well in nutrient-poor soils; however, a monthly application of a balanced such as NPK 10-10-10 during the active growth phase supports healthy development. Pinching the growing tips when reach about 30 cm in height encourages bushier growth and more flowers. Common pests include and , which can be effectively managed with applications as an organic control method. Fungal diseases, particularly , may occur in humid areas, but fungicides should be used sparingly, with emphasis on cultural practices like good spacing and drainage for prevention. For harvesting, stems should be cut at the bud stage when the outer s begin to open, preserving the flower's structure for drying. Bundles are then hung upside down in a dark, well-ventilated area for 1-2 weeks until fully dried, retaining their color and shape.

Cultivars and commercial varieties

Numerous cultivars of Xerochrysum bracteatum have been developed over many years through selection and hybridization, primarily for enhanced bract colors, varied plant heights, and improved flower longevity, with forms dominating commercial production. These breeding efforts, originating in and continuing in , have expanded the natural golden-yellow bracts to include shades of white, pink, red, purple, orange, and bronze, enabling diverse applications in gardens and floristry. Notable perennial cultivars include 'Dargan Hill Monarch', a naturally occurring Australian form with grey foliage, reaching 80 cm tall by 1 m wide, featuring large golden-yellow flowers suitable for borders and cut arrangements. Similarly, 'Cockatoo' is a low-growing sub-shrub (around 80 cm tall) with lemon-yellow bracts surrounding orange disc florets, valued for its compact habit in pots and as a cut flower. 'Wallaby Sungold' offers a compact, ground-covering growth (up to 50 cm wide) with golden blooms from spring through autumn, ideal for mass plantings. Annual varieties emphasize vibrant mixes and specialized traits, such as 'Flobrafla', a mounded perennial-like form with yellow-red bicolored bracts, bred for dried floral use in full-sun, dry soils. Dwarf selections like 'Crimson' and 'Shades of Pink' grow to about 30-50 cm, producing true-breeding red or pink-toned flowers for and bouquets. F1 hybrid mixes, such as those from commercial seed lines, provide uniform height and color for the cut-flower industry, often in multicolored blends like , , and . Breeding has focused on true-breeding seed lines for consistent color and habit, with some cultivars resulting from crosses with related species like Helichrysum bellidioides. Commercially, X. bracteatum cultivars are a staple in the dried flower trade due to their papery bracts that retain color and shape when air-dried, comprising a significant portion of everlasting flower production for arrangements and crafts. They also feature in fresh bouquets for their long vase life and as potted in nurseries, with typically from or cuttings to maintain variety traits.

References

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