Eryngium ovinum is known as the Blue Devil
Eryngium ovinum is a perennial herb, to about 60 cm tall, forming clumps, often with a green to metallic blue-to purple colour overall. It resembles some sort of ‘weedy-thistle’ on first glance.
It is very common in NSW, growing on the tablelands and western slopes mainly, into the south-western plains (as far west as around Deniliquin). It extends in Victoria around these western parts (south from Albury) and is found generally through the northern central areas and south-west of the state. It extends in South Australia, growing in separate patches; north of Mt Gambier; around Adelaide and further north around Burra, Clare and Saddleworth. It just extends into Queensland, growing west of Warwick and Toowoomba. It is also found around the Hobart-area in Tasmania, and further north-east near Pontypool. It is a threatened species here.
It is found in dry sclerophyll woodlands as well as paddocks and other disturbed areas including road verges, often on sandy to sandy-clay soils.
Eryngium spp. have simple and opposite leaves, which come as basal leaves and flowering-stem (cauline) leaves. They can be entire, palmately or pinnately-lobed (pinnatisect), often spinose and very prickly. In this species, basal (rosette) leaves are pinnatisect to 25 cm long, with a central wider strip to about 1 2 cm long and fine prickly teeth extending off – making leaves about 4 cm wide; with an overall waxy texture. Cauline leaves are to 6 cm long and up to 1 cm wide, less divided than basal leaves; generally green in colour.
Eryngium spp. have flowers in compound-dichasia. This is simply a structure where each flowering shoot branches in two to form two new flowering shoots, each of which divide again in the same manner and so on until a limit is reached. The inflorescences consist of linear showy prickly bracts along a flowering striated stems, which gradually decrease in size along the inflorescence until a “head” is formed at the terminal of the stems, surrounded and interspersed by many prickly bracts; the head is composed of 5-merous bisexual flowers, each about 5 to 10 mm across, somewhat tubular to more open at the apex, with stamens and carpels protruding; deep mauve or blue in colour with the flowering stems also the same colour. This all results in a spiky-looking purple-blue plant which is highly unsual in the Australia landscape. Flowering starts in early summer; with plants generally dying back in autumn.
The fruit are bascially mericarps to 4 mm long, covered with acute scales which appear like sacks.
This species is known to be cultivated and sold. Although, other species may be more popular.
It might not be preferred due to its prickly and somewhat weedy-looking nature but the blue-purple colour is certainly interesting. It could be grown in a formal layout with precise spacing, in a rockery or open bed to create a display.
The Blue Devil would make an eye-catching addition to a cottage garden or rockery.
This would have to be the plant with the most unusual appearance in our cold climate garden (near Armidale, NSW).
Best grown in full sun on well-draining soil – away from other plants so it can be admired.
Propagate from seed.
The species is mentioned by Alan Cunningham in a paper On the Botany of the Blue Mountains published in Geographical Memoirs of NSW, 1825. Cunningham mentions that “Plants when young, much sought after by sheep in the plains around Bathurst”. This would account for the Blue Devil’s demise in grazed areas.
This species likely regenerates from seed after fire.
Eryngium is a genus of 250 species, growing in many parts of the world in tropical and warm-temperate areas. Australia has about 7 recognised native species. NSW currently has 5 formally recognised native species, 2 weed-species, and a further 4 taxa that are informally recognised at this stage.
Eryngium – an old genus name from Ancient Greek ereugomai (ἐρεύγομαι) which means to “belch”, “vomit” or “emit”. Pedanius Dioscorides reported that these plants were excellent for any matter associated with gut-cramps and gas.
ovinum – Latin – meaning ‘sheep” or “of or belonging to sheep” – capturing Alan Cunningham’s observation that sheep readily ate this species.
This species is not considered to be at risk of extinction in the wild in most states it occurs. It is listed as threatened with extinction in Tasmania.
NSW Flora Online (PlantNET) – Eryngium ovinum profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eryngium~ovinum
Gardening with Angus – Eryngium ovinum profile page https://www.gardeningwithangus.com.au/eryngium-ovinum-blue-devil/
Tasmania Threatened Species Link – Species Management Profile – Eryngium ovinum profile page https://www.threatenedspecieslink.tas.gov.au/Pages/Eryngium-ovinum.aspx