This species was previously placed on the Red List as Hebe barkeri, but it has now moved to the genus Veronica.

Veronica barkeri is a small tree endemic to New Zealand, where it occurs on the Chatham Islands, on Chatham, Pitt and South East Islands. There are now fewer than 250 mature individuals estimated left in the wild, and this is a decline of more than 50% since 2002 (i.e. one generation of this species), when the last full census for this species was carried out. With only 50–100 mature individuals thought to be secure it is extrapolated that, when combined with the coming two generations, the species could decline by 80–90%. The main threat to the species is invasive species, and without browsing animal control this species will go extinct. It is assessed as Critically Endangered under criterion A4ace.

This species is endemic to New Zealand, where it occurs on the Chatham Islands, and is found on Rēkohu / Wharekauri / Chatham, Rangihaute / Rangatira / Pitt and Hokorereoro / Rangatira / South East Islands. Distribution map is generalised.

The last comprehensive census for Veronica barkeri was undertaken in the early 2000s', when a total population of 525 mature individuals was recorded. Since then, this species has continued to decline, and outside restoration plantings and the few managed populations within reserves there has been considerable loss of wild plants (de Lange et al. 2010, de Lange 2023). The wild population of this species is now estimated to have less than 250 mature individuals. The only functional natural population of Veronica barkeri is in the Tuku Nature Reserve, where there is c. 50–100 mature trees, outside this site most trees are senescent, or in sites which offer little opportunity for long-term survival. There is no recruitment outside managed reserves and restoration sites, with the species' persistence depending entirely on intensive browsing animal control and creating open sites for seed to germinate in. Recognising its plight, the New Zealand Indigenous Vascular Plant Threat Listing Panel assessed this species as ‘Threatened / Nationally Critical’ citing criteria B – ‘small population (natural or unnatural) with a moderate ongoing or predicted decline of 50–70%’ and B1 population of 250–1,000 mature individuals’, although it is estimated that numbers could be even less than 250 mature individuals now, and qualifying this assessment ‘CD’ [Conservation Dependent], ‘IE’ [Island Endemic] and ‘RF’ [Recruitment Failure] (de Lange et al. 2018, 2024). With only 50–100 mature individuals thought to be secure it is suspected that combined the past generation with the coming two generations the species could decline by 80–90%.

Veronica barkeri is one of the tallest trees on the Chatham Islands, with specimens reaching up to 13 m tall (de Lange et al. 2010, de Lange 2023). For a Veronica species plants are also reasonably long-lived, with some specimens known to be over 30 years old. There is some evidence that isolated plants have lower seed set, with the inference that this species may have some level of self-incompatibility. While the species usually produces hermaphroditic flowers some plants appear to have female (rudimentary stamens, or stamens with poor pollen set) and male flowers (rudimentary stigma) and this also needs further study. Fresh seed germinates readily but loses viability within a year or so on storage. There is considerable difference in flower colour across the islands, with those from northern Rekohu / Wharekauri / Chatham Island plants with pale mauve flowers that fade white, whereas those from the south have darker mauve flowers, and those from Rangihaute / Rangiauria / Pitt Island are usually darker blue or even pink (de Lange et al. 2010, de Lange 2023).

The ecology of this species is poorly understood. Cockayne (1902) noted it was a component of taller forest, and that it grew in canopy gaps, along water ways and in recently disturbed ground. Currently the species remains a scarce component of open forest and scrub, with an apparent preference for coastal scarps, forested streamside’s, and the banks of incised streams (de Lange 2023). Plants often start life epiphytic on tree fern (Alsophila, Dicksonia) trunks. In places where the range of Veronica barkeri and V. dieffenbachii overlap hybrids may be found.

Veronica barkeri may have always been an uncommon component of the forest associations of the Chatham Islands. Indeed, it is notably absent from the early collections made from the islands by Dieffenbach and Travers and was only recognised as a distinct species by Cockayne (1899). Undoubtedly the species underwent a major decline following human settlement of the islands 600–700 years ago, a decline which accelerated following unrestricted access to forest remnants by livestock, feral pigs (Sus scrofa) and possums (Trichosurus vulpecula). The species is extremely palatable, and yet if browse pressure of controlled will recover rapidly. For example, at the onset of browsing animal management of the Tuku Nature Reserve for Chatham Islands Pigeon/parea (Hemiphaga chathamensis) and Magenta Petrel/taiko (Pterodroma magentae) during the late 1980's and 1990's, Veronica barkeri seedlings were noted appearing in their hundreds along portions of the Tuku River and the exposed, partially deforested ridgelines above the catchment. Forest regeneration and old age has resulted in the natural decline of many of these plants, but the recovery serves as an indication of what management is needed. It is also clear that without browsing animal control this species will go extinct. Veronica barkeri has been successfully established at two reserves, Chudleigh and Nikau Bush, where mixed provenance plantings has resulted in self-sustaining populations, again offering hope for future management.

This species is very uncommon in cultivation in Aotearoa / New Zealand.

The immediate threats to Veronica barkeri are habitat deterioration and the resulting loss of populations outside browsing animal management – which is a serious issue on the two larger islands in the Chatham group. The species is also naturally declining from the Tuku Nature Reserve due to forest succession; some effort is needed there is create canopy gaps and other places for plants to regenerate into. Forest remnants containing this species should be secured and fenced to exclude feral pigs and livestock.

There is urgent need for more research. In particular determining the extent of genetic variability in the species, which shows considerable follower colour differences across the island, is needed to help guide restoration plantings, and also to determine the extent of hybridism between this species and the other two endemic Veronica, V. chathamica and V. dieffenbachii. The ecology of the species needs critical assessment, particularly with respect to managing disturbance regimes to maximise recruitment. The reproductive biology also needs study to determine if field observations suggesting there may be female and male sex-types as well the more usual hermaphrodites, and self-incompatibility are valid.