Lack of ecological knowledge is a major challenge for effective conservation of threatened plant species in Australia as disturbance events, such as wildfire, increase in frequency and magnitude. Rapid on-ground surveys are increasingly important to inform recovery strategies for rare and threatened plants in response to extreme wildfire events, yet resources are rarely available to deploy time-sensitive surveys. Here, we utilize a rapid on-ground survey and monitoring program to document basic biological and ecological information for 21 rare and threatened plant species from the New England bioregion in northern New South Wales, which were affected by the catastrophic 2019–2020 megafires. Our results fill an important knowledge gap of ecology, population size, distribution and response to fire for these taxa, document for the first time a species distribution pattern within the Torrington State Conservation Area and reveal previously undocumented plant–insect interactions for nine species, including likely pollination of Persoonia terminalis ssp. terminalis and Monotaxis macrophylla by native bee (Hymenoptera) and fly (Diptera) species. Our findings reveal that two species (Cassinia heleniae and Hakea macrorrhyncha) have scarce distribution and low population sizes, despite neither having a conservation listing and their threat status should be urgently assessed. Simple rapid on-ground surveys can be more cost effective for delivering long-term conservation outcomes for rare and threatened taxa and we advocate that future funding and prioritisation processes must support the immediate delivery of such surveys in response to disturbance events.