An erect or spreading shrub to a height of 1.5 metres.
It has a limited distribution, growing from the north of Sydney, to Gosford and then north-west into Yengo NP. It grows on sandstone-derived soils.
Leaves are arranged alternately and are narrow-cylindrical (terete), to 30 mm long and about 0.5 mm wide, hairless when mature.
Persoonia flowers are typically produced either solitarily, or, in a raceme-like arrangement which can grow on into a leafy shoot. The flower structure is very similar to genera such as Hakea and Grevillea; a perianth of 4 tepals (either sepals or petals) is at the base, 4 stamens which rise above the perianth (the anther bases can be fused to the tepals or free), surrounding one carpel (female part); almost always yellow in colour.
In this species, the tepals are to 8 mm long, fused at the base, with the tips rolled back, with overall flowers yellow and about 15 mm wide by 20 mm long.
Flowering occurs from January to July.
The drupes are smooth and green, usually with reddish-purple blotches.
Not known to be currently cultivated and no information is available.
It would make an attractive plant for Sydney gardens on sandy/sandstone soils. It has dense thin leaves and a nice texture.
It may be more widely cultivated in the future.
Generally difficult from seed or cuttings and seed needs to be scarified and sown as soon as fresh. Propagation of Persoonia species is becoming more common in nurseries and working with the seeds has attracted many amateur attempts; but with large amounts of resulting frustration.
There is advice that the outer fruit coating (the exocarp) needs to be clipped to open it up, and then the seed put into a solution containing the plant propagation hormone GA (Giberellic Acid) for several hours to days. This will trigger the seed to germinate.
Other techniques include putting fruits in a bag with potting mix for 12 months and storing in a glass house / propagation shed, then clean and sand the fruits and then sow, with germination taking another 6 months (information from Sutherland Shire Bushcare).
Persoonia is a genus of about one hundred species all of which are endemic to Australia.
It is reported that the fruit can be eaten raw or cooked, succulent but astringent. The fruit has a sweet fibrous pulp that is fixed to one large seed. It tastes somewhat like sweet cotton wool and is relished by First Nations Peoples of Australia.
The term geebung is derived from the Dharug language word geebung, while the Wiradjuri term was jibbong.
P. isophylla is similar to P. pinifolia but the flowers of that species have small leaves at their base, where the flowers of P. isophylla have full-sized leaves at their base. The two species sometimes grow together but hybrids between them are rare.
Plants are likely to be killed by fire regenerate from seed. Although, some suckering and reshooting of stems may be possible.
Persoonia is a genus of about 100 hundred species, all endemic to Australia, occurring in all states and territories. NSW currently has around 51 species – some of which are species complex with many subspecies taxa, and some which are threatened with extinction.
Persoonia – named after Christiaan Hendrik Persoon (1761-1836), a South African botanist and mycologist who is most well-known for describing mushroom species. The genus was named in his honours by James Edward Smith (1759-1828), an English botanist and founder of the Linnean Society.
isophylla – is derived from the Greek; isos (ίσος) meaning “equal” and phyllon (φύλλοv) meaning “leaf”. This refers to the equal full length of leaves beneath (subtending) the flowers.
This species is not considered to be at risk of extinction in the wild, but has a limited distribution.
NSW Flora Online (PlantNET) – Persoonia isophylla profile page
Wikipedia – Persoonia isophylla profile page https://en.wikipedia.org/wiki/Persoonia_isophylla