Grevillea juniperina
Juniper-grevillea
Juniper-grevillea
Wikipedia links: Angiosperms > Eudicots >Proteales > Proteaceae> Grevillea juniperina
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Common name: Juniper-grevillea
Also, juniper-leaf grevillea or prickly spider-flower
Conservation status: Vulnerable
Subspecies juniperina is listed as a vulnerable species on Schedule 2 of the Threatened Species Conservation Act 1995 in NSW
Its habitat is threatened by housing development, road upgrading, inappropriate fire regimes, weed invasion, rubbish dumping and trampling either by people or cars
Etymology:
The genus was named in honour of Charles Francis Greville, an 18th-century patron of botany and co-founder of the Royal Horticultural Society
Flowers:
The flower heads, known as inflorescences, are mostly red, orange or yellow
Flowering occurs throughout the year, peaking between midwinter and early summer, though it varies between the different subspecies
Subspecies allojohnsonii flowers from September to February
Subspecies trinervis flowers from August to December,
Subspecies juniperina, amphitricha, sulphurea, villosa and fortis flower in August and September
The spider-flower arrangement of the inflorescence has several individual flowers emerging from a central rounded flower head—reminiscent of the legs of a spider
The flowers are red, pink, orange, yellow or greenish, and are mostly terminal—arising on the ends of stems—though they occasionally arise from axillary buds
They are 2.5–3.5 cm long
The perianth is finely furred on the outside, while the pistil is smooth; it is 1.5–2.7 cm long
Fruit:
Seed pods, each capsule is 10–18 mm long, and releases one or two seeds when ripe
The narrow oval seed is 7.5–12 mm and 2.2–3.3 mm wide, with a swelling at the apex and a short wing
Both surfaces are covered with tiny hairs
Leaves:
The prickly leaves are generally stiff and are 0.5–3.5 cm long and 0.5–6 mm wide
They are crowded along the stems
Stem & branches:
The branchlets are thick and sturdy
Roots:
Habit:
A prickly-leaved shrub
A spreading or erect growth form
It grows to between 0.2–3 m in height
Habitat:
Generally grows on clay-based or alluvial soils in eucalypt woodland - see below for additional information related to sub-species (in Distribution)
The annual rainfall in regions where G. juniperina grows is 600 to 800 mm
Distribution:
Native to eastern NSW and southeastern Queensland in Australia
Subspecies allojohnsonii is found on the Northern Tablelands and North West Slopes in northern NSW, from Walcha north to Tenterfield and Stanhope and Girraween National Park in southern Queensland
Subspecies amphitricha grows in woodland and grassland on slopes and ridges between Braidwood and Nerriga in the Shoalhaven River catchment on the Southern Tablelands
Subspecies fortis grows in forest, woodland and shrubland and is found on rocky hills and slopes near watercourses, specifically along Ginninderra Creek, the lower reaches of the Molonglo and Cotter Rivers, and the Murrumbidgee River from Pine Island downstream to where it is joined by the Molonglo River—mostly within the Australian Capital Territory
Subspecies juniperina grows in forest or woodland and is found in Cumberland Plain and Castlereagh Woodland communities on clay-loam soils
Subspecies sulphurea grows on alluvial soils, often with Leptospermum species, along riverbanks and is found in the catchments of the Coxs, Kowmung, Wollondilly and Shoalhaven Rivers in the Central and Southern Tablelands, from Tallong to Berrima, as well as Lidsdale to Jenolan State Forest in the southwestern Blue Mountains
Subspecies trinervis is found in the western Blue Mountains where it grows on alluvial soil with poor drainage in woodland or along riverbanks
Subspecies villosa is found along watercourses in eucalypt forest east and northeast of Braidwood, as well as near Currockbilly in southeastern NSW
Additional notes:
Similar species include:
Wingello grevillea (Grevillea molyneuxii), which can be distinguished by its prominent midvein on the leaf undersurface
Red spider-flower (G. speciosa), which has wider leaves with lateral veins and longer pistil
Ecology
Killed by bushfire, Grevillea juniperina regenerates afterwards by seeds that germinate after lying dormant in the soil, stimulated by exposure to heat and smoke
Plants over 1 m high produce more seed
Intervals of 10 to 15 years between fires are thought to be most beneficial for the species' survival, as this allows seed numbers to build up in the soil over time.
Grevillea juniperina can also colonise disturbed areas, though overgrowth of Bursaria spinosa can negatively impact its spread
Grevillea juniperina is pollinated by birds, with bees also recorded visiting flowers
The leaves are food for caterpillars of the cyprotus blue butterfly (Candalides cyprotus)
Taxonomy
Grevillea juniperina is a plant of the family Proteaceae
The type specimen for this species was collected from the Port Jackson area (Sydney district) and was described by botanist Robert Brown in 1810, who gave it the specific epithet juniperina that alludes to its juniper-like foliage
Likewise, it is commonly known as juniper- or juniper-leaf grevillea, as well as prickly spider-flower
The lectotype was selected by Don MacGillivray in 1993 from a collection by George Caley in 1803 11 km northwest of Prospect in what is now Sydney's outer western suburbs
Brown placed it in the series Lissostylis in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen
English botanist and explorer Allan Cunningham collected what he called Grevillea sulphurea in 1822 near Coxs River in the Bathurst area, where it grew alongside G. rosmarinifolia and G. arenaria subspecies canescens
This was later synonymised with G. juniperina, before being recognised as a distinct subspecies.
George Bentham placed G. juniperina in Section Lissostylis in his 1870 Flora Australiensis
This section has become the Linearifolia group of 45 species of shrub in southeastern Australia
Within this group, G. juniperina is classified in the Speciosa subgroup, five species of bird-pollinated grevilleas found in eastern Australia
The others are G. molyneuxii, G. dimorpha, G. oleoides and G. speciosa
In 2000, Robert Owen Makinson described seven subspecies of G. juniperina in the Flora of Australia, and the names are accepted by the Australian Plant Census:
G. juniperina subsp. allojohnsonii Makinson is a prostrate shrub to 30 cm high with red flowers
G. juniperina subsp. amphitricha Makinson is a prostrate or spreading shrub with yellow or orange flowers that grows to 0.2–1.2 m tall and 3 m wide
G. juniperina subsp. fortis Makinson is a vigorous red-flowered shrub growing to 1–3 m tall
G. juniperina R.Br. subsp. juniperina is a spreading shrub that is 0.5–1.5 m high
G. juniperina subsp. sulphurea (A.Cunn.) Makinson is a shrub up to 2 m high
G. juniperina subsp. trinervis (R.Br.) Makinson (formerly Grevillea trinervis) is a prickly shrub with a spreading or prostrate habit ranging from 0.5–1.2 m, or rarely 2 m and has yellow, orange or red flowers
G. juniperina subsp. villosa Makinson is an upright red- or yellow-flowered shrub up to 2 m high
Subspecies sulphurea hybridises with G. juniperina subsp. trinervis in the southern and western Blue Mountains
Use in horticulture
Grevillea juniperina adapts readily to cultivation and has been important in horticulture as it is the parent of many popular garden hybrids
Allan Cunningham sent seed of G. juniperina to England in 1820; it was grown there the following year
Baron Charles von Hügel grew the species in Vienna in 1831
It has been grown outdoors in southern England, particularly G. juniperina subspecies sulphurea
Grevillea juniperina adapts easily to cultivation and grows in a wide range of soils and aspects in locations with good drainage
Long-flowering, it attracts birds such as honeyeaters with its nectar
The prickly dense foliage is also a good nesting site and shelter, particularly for smaller birds, such as finches
Many forms and hybrids have been commercially propagated and sold, some having more horticultural appeal than others
Low winter temperatures promote more prolific flowering and pruning promotes dense foliage
Plants are readily propagated by cuttings or seed, although propagation by cuttings is required to ensure the new plants have the same characteristics of the parent
Direct contact with the plant may cause a skin rash
Many cultivars have been selected for horticultural use, either selected forms or hybrids with other Grevillea species
One prominent early breeder was Leo Hodge of W Tree, Victoria
Hodge became interested in breeding grevilleas after finding seedlings in his garden
His first trials involved crossing G. juniperina with G. victoriae, producing G. 'Poorinda Queen', which was the first to flower, followed by G. 'Poorinda Constance', G. 'Poorinda Leane' and G. 'Poorinda Pink Coral' respectively, all in 1952
Cultivars include:
'Allyn Radiance' – derived from a prostrate orange and prostrate red forms of G. juniperina
'Audrey' – G. juniperina crossed with G. victoriae. Bred in 1957 by George Althofer, who named it after his wife; it grows to 2 m high and wide and produces orange-red flowers over many months - it is popular in South Africa and the USA
'Canberra Gem' – G. juniperina crossed with G. rosmarinifolia. Registered with the Australian Cultivar Registration Authority in 1976
'Canterbury Gold' – prostrate yellow form of G. juniperina crossed with Grevillea parvula
'Goldfever' – G. juniperina crossed with Grevillea rhyolitica
'H22' (Gold Cluster) – a dense growing prostrate selection with yellow flowers
'Lunar Light' – a low-growing form with variegated leaves and orange-pink flowers; it is suitable for rockeries
'Molonglo' – a form with a low–spreading habit and larger orange flowers with red styles. It was bred by Rudolph Willing of Australian National University in 1964, from two disparate forms of juniperina, an erect red-flowered form from around Canberra and a yellow-flowered spreading prostrate form from the western slopes of the Budawang Range in 1964. It is named after the Molonglo River.
'New Blood' – a compact red-flowered shrub resulting from a cross of 'Molonglo' cultivar with G. rhyolitica
'Old Gold' – a low spreading shrub with yellow new growth, lobed leaves and greyish-yellow flowers with pink styles; it is derived from G. juniperina crossed with Grevillea ilicifolia
'Orange Box' – G. juniperina crossed with G. victoriae
'Pink Lady' – G. juniperina crossed with G. rosmarinifolia. Bred by Stan Kirby of Queanbeyan, grown widely in early 1970s; a shrub to 60 cm high & 3 m wide with pale pink flowers
'Poorinda Adorning' – a seedling that grew in Hodge's garden, registered in 1978; the original plant grew in 1965
'Poorinda Annette' – a cross with the small-flowered form of Grevillea alpina
'Poorinda Beauty' – a cross with Grevillea alpina
'Poorinda Belinda' – a cross with a hybrid of the yellow flower form of Grevillea obtusiflora and Grevillea alpina
'Poorinda Constance' – a cross with Grevillea victoriae
'Poorinda Jeanie' – a red-flowering shrub that grows up to 2 m high; it is derived from a cross with Grevillea alpina
'Poorinda Leane' – a cross with G. victoriae; it is a spreading shrub to 4 m high with buff or apricot flowers
'Poorinda Pink Coral' – a cross with G. victoriae, named for the colour of its flowers
'Poorinda Queen' – derived from a cross with a yellow-flowered form of Grevillea victoriae; it has apricot-pink flowers
'Poorinda Refrain' – a cross with Grevillea floribunda
'Poorinda Rachel' – a 1 m high hybrid cross with Grevillea alpina, which has buff-cerise flowers, and was developed in 1965–66
'Poorinda Rosalie' – a taller rose-red flowered hybrid with G. victoriae, developed in 1967–68
'Poorinda Signet' – a cross with Grevillea lanigera × semperflorens – a hybrid of English origin derived from a cross of Grevillea juniperina var. sulphurea with Grevillea thelemanniana
Sources of information: