A shrub up to 3 metres high, often found from very small to potentially large.
It has a mostly coastal occurrence in NSW, growing from as far south as around Ulladulla, extending north into the Southern Highlands, Greater Sydney Basin and Blue Mountains, as far west as north of Lithgow. It grows along the north coast and northern tablelands (east of Guyra and Glen Innes). Records move just into SE Queensland but they are scant here.
It typically grows in heathland, shrubland and dry sclerophyll woodland and forest, on sandstone-based and sandy soils.
Petrophile spp. have a somewhat complicated leaf structure. Leaves are simple but are strongly divided into segments, usually in the upper half of the leaves with the lower half acting as a linear petiole or stalk. This can be referred to as strongly pinnatisect. Sometimes, leaf segments are ternately-divided (into groups of 3). The leaf segments are also terete (tubular). They are arranged alternately.
In this species, they are to 10 cm long by up to 5 cm wide, with the undivided basal part about the same length as the divided part. The divided segments are terete but not sharp to the touch, erect to ascending, mid to dark green in colour.
Petrophile spp. have many small flowers arranged in a compressed spike or ‘head’, formed in the leaf axils and terminals, with all flowers surrounded by bracts which become more woody as the inflorescence begins to fruit. Flowers have 4 tepals in the perianth, a typical Proteaceae feature, but flowers are more symmetrical in this genus. In this species, the small flowers are cream to pale yellow in colour, very linear and about 2 cm long, occurring in elongated clusters about 30 to 40 mm in size. Flowering occurs in late spring and early summer.
The fruit is technically a nut (which differs to a lot of other genera in the family). The nuts are formed within the resulting fruiting cluster of the inflorescence which has an elongated cone-shape and holds the nuts in the woody bracts. Each nut is about 4 mm long and is hairy. The fruits remain on the plant for an indefinite period and only release the seeds after a fire or the death of the plant.
Petrophile species were first introduced to cultivation in the 18th century, but these days are rarely seen outside specialist botanical and enthusiast’s gardens.
They are known to be cultivated and can do well in the right conditions.
This species requires a sandy, free draining soil in full sun.
This Editor has planted one plant on a sloping sandstone bed and it is establishing well.
They may die quickly due to strong wind or poor drainage due to heavy rain. But well worth growing.
They can be grown from seed which germinates well if fresh, although germination times may be variable from the same batch and so seed trays should be kept for some time before being discarded. Another thought for improving germination may be to remove the hairs on the nuts that seems to repel water, or nick the nuts to allow water to get to the seed embryo.
Seed is available commercially.
Propagation can also be carried out from cuttings taken from semi-firm new growth, and treated in the regular way with the warning that the hairy leaved species should not be misted too much for fear of fungal disease.
This species is distinguished from P. pedunculata by its flowerheads that are on peduncles 10 to 30 mm long.
This species often occurs in the same general area as P.sessilis and P.canescens. Intermediate forms between P.pulchella and the other two species are known to occur.
Petrophile is a genus of approximately 63 species with the greatest diversity being in the south of Western Australia. They also occur in Queensland, NSW and South Australia. NSW currently recognises 4 species.
Petrophile spp. will generally generate from seed after fire. This species can be seen in vast quantities in sandstone areas after fire.
Petrophile – from the Greek words petra (πέτρα) = “stone” or “rock” and philia (ϕιλία) meaning “loving” or “preferring” – referring to many species being found on rocky-habitats
pulchella – from the Latin, pulchellus, meaning beautiful.
This species is not considered to be at risk of extinction in the wild.
The Australian Native Plants Society (Australia) fact sheet for Isopogon and Petrophile: https://anpsa.org.au/APOL29/mar03-3.html
The Australian Native Plants Society (Australia) fact sheet for Petrophile pulchella https://anpsa.org.au/plant_profiles/petrophile-pulchella/
Wikipedia – Petrophile pulchella profile page https://en.wikipedia.org/wiki/Petrophile_pulchella
Plants of South Eastern New South Wales – Lucidcentral/Online Identification app – Petrophile pulchella profile page https://apps.lucidcentral.org/plants_se_nsw/text/entities/petrophile_pulchella.htm
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia