This study presents the results of the investigations into the ecology of the threatened shrub species (Scrophulariaceae) Hebe armstrongii, Mt White, Canterbury, New Zealand.

There are four populations of Hebe armstrongii located in the study area (Nigger Valley) comprising of 1730 plants. All four populations had similar population structure in terms of height and canopy spread classes and regeneration. Throughout these four populations there was an observed absence of juveniles, indicating a lack of regeneration although plants were found to be flowering and setting seed.

Herbivory, which has previously been the documented limiting factor in the regeneration of this species, appeared to have no affect on regeneration in the present study. There were no significant differences in population structure or health between open and enclosed areas.

There are four vegetation communities identified within the study area, two predominately grassland communities and two grassland-shrubland communities. Hebe armstrongii was associated with two vegetation communities; a community dominated by Halocarpus bidwillii and to a lesser extent a community dominated by Ozothamnus leptophylla and Agrostis capillaris. These communities were distributed on Big Flora and Little Flora terraces and on the island in the Mounds of Misery. Moss and Leucopogon colensoi were the species most frequently associated with Hebe armstrongii, while the shrub species Halocarpus bidwillii and Ozothamnus leptophylla to a lesser extent.

With the implementation of the management by research suggested by this study, the further decline and possible extinction of wild Hebe armstrongii populations may be avoided.