Pherosphaera fitzgeraldii (F.Muell.) F.Muell. ex Hook.f.

For many years Pherosphaera fitzgeraldii was arguably the most famous conifer in Australia’s Blue Mountains, chiefly on account of its great rarity but also for its incredibly niche habitat in the spray zone of south facing waterfalls (Grant 2025). Its fame would be eclipsed following the discovery of the Wollemi Pine (Wollemia nobilis) in 1994, but the threats facing P. fitzgeraldii are just as severe as those facing Wollemia, arguably even more so, but it has not benefitted from the sophisticated marketing campaign that has made Wollemi Pine a household name and a common tree in gardens all over the world. Being an aesthetically challenged shrub rather than a passably ornamental tree cannot have helped. Nevertheless, learning from the programme managing Wollemi Pine, Blue Mountains Botanic Garden staff have recently identified every wild plant and each is now being propagated to ensure the preservation of all known genotypes (Grant 2025).

Identifying and georeferencing each plant in the wild is no easy task given their predisposition for precipitous, slippery waterfalls and generally inaccessible sites, so abseilers have been engaged to assist these efforts (Grant 2025). The use of novel methods to identify and survey sub-populations is reflected in a general increase in the numbers of known individuals: in 1981 the figure stood at 203; in 1994 it was 455; in 2014 it was 755; but by 2021 24% of 159 revisited plants had died and a further 22% of 159 were showing signs of stress (Smith 1981; Thomas 2019; McMaster et al. 2024). In their conservation genomics study McMaster et al. found evidence of two distinct genetic groups among the population; they also found evidence of clonality (multiple ‘individual’ plants representing only a single genotype, a common survival mechanism in plants restricted to particularly specialist habitats) as well as inbreeding and genetic depletion (McMaster et al. 2024). These results are now informing both in situ and ex situ conservation priorities.

Pherosphaera fitzgeraldii is incredibly rare in collections within our study area. A few genotypes have historically been maintained in botanic gardens, and the work now being undertaken by the Blue Mountains Botanic Garden will signfiicantly bolster the range of genotypes maintained in ex situ collections, at least in Australia. Selected forms could prove garden worthy, which may help to focus increased attention on the role horticulture has to play in plant conservation, especially of Critically Endangered taxa. P. fitzgeraldii has been cultivated in UK collections for some time, including the Sir Harold Hillier Gardens (Edwards & Marshall 2019), although its date of introduction seems not to have been recorded (for further discussion on this point, see the account for P. hookeriana). It maintains a toehold in cultivation in other locations, for example a single plant is recorded from Pukeiti, Taranaki, New Zealand (Taranaki Regional Council 2025).

The limited horticultural experience of this plant does suggest, however, that Pherosphaera fitzgeraldii is not as demanding in cultivation as its niche wild habitat might suggest: plants traceable to the Hillier Gardens stock, and afforded no special treatment, have survived in several UK gardens, notably a young potted plant at Cluny House Gardens in Perthshire which has survived temperatures as low as –10°C (TC pers. obs.), a remarkable distance from the ‘somewhat subtropical conditions’ (Debreczy & Rácz 2011) the species is used to in the Blue Moutains. An expedition from Wakehurst introduced new material to UK collections in the early 2000s under the collector code ETAZ 76. Plants raised from this introduction are established, among others, at Wakehurst and Windsor, neither of which is any stranger to frost and snow. On the basis of these observations we have given an RHS hardiness rating of H4 (roughly equivalent to USDA 9a), whereas the Hillier Manual maintains a more cautious H3 (Edwards & Marshall 2019). Either way, such resilience surely offers hope for its long term survival.