Epilobium hirtigerum, hairy willow herb, is a critically threatened plant. How threatened you may ask? Well locally this plant has been termed the ‘Hobsonville kakapo’ because its threat status matches that of the charismatic kakapo. The hairy willow herb has tiny white flowers, seed pods packed with 100 fluffy seeds ready for dispersal, and takes a liking to roadsides.
Botanic Gardens visited a site in west Auckland, where a large population of E. hirtigerum has been growing on a property used for plant production. Most sightings of this plant have been in wasteland areas and the threat of development is high for this species. The plants were growing in the scoria surfaces or the heavily compacted areas that were used as pathways or vehicle access. Despite this plant being threatened, it is profusely seeding out at this site so the conditions for its growth are ideal. Students are working on understanding the environmental conditions that are promoting the E. hirtigerum growth. The findings from the student projects will help to inform future management of the site to preserved and promote this threatened species. The site also has competition from environmental weeds which are under active management.
Botanic Gardens staff, Emma, and local Biosecurity officer, Mary, collected seed off nearly 100 plants that was sent to the New Zealand Indigenous Flora Seed Bank in Palmerston North. The tiny, fine seed is incredibly hard to count, let alone test its ripeness. But with seed spotted all over the site, timing for seed collection was at the plant’s natural dispersal stage. We hope that some of the genetic diversity in this species will be preserved and future conservation projects will benefit from this collection.
You can read more about the conservation status of this plant in the latest Conservation status of New Zealand indigenous vascular plants, 2017.