22-05-2025
Threatened plant gets a helping hand
Craspedia argentea flowers at Dunedin Botanic Garden. PHOTO: SUPPLIED
Craspedia argentea is a real trooper of a herb, holding on for dear life in Otago. This small Asteraceae plant grows in rosettes of downy silvery leaves encircling stems atop which spherical flowerheads called "glomerules" sit. Each glomerule opens out into many tiny, pale yellow flowers in spring. It survives in Central Otago, on exposed land sparse of vegetation and subject to the more extreme sides of New Zealand's temperature ranges. Few remain in the wild, making this Craspedia one of New Zealand's most threatened plant species.
At Dunedin Botanic Garden, we have been involved in the conservation of this precious native plant since early 2024. At the request of the Department of Conservation (Doc), we received a small number of these plants via Manaaki Whenua — Landcare Research, and have been caring for them at our propagation nursery. Our aim is to produce more plants and seeds ex-situ to eventually help boost population numbers in-situ.
Challenges include managing different environmental conditions to the plant's natural home base, such as Dunedin's humidity. In the nursery setting, these plants are sheltered, in well-draining media, and have a careful irrigation plan. Caring for a plant with such a long tap root is another part of the puzzle. We also conducted a hand-pollination trial, thought necessary due to lack of natural pollinators in Dunedin. Happily, several hundred filled seeds were produced by the end of the season. These have now been sown, with many germinating, which is a promising sign of things to come.
Garden Life is produced by Dunedin Botanic Garden. For more details, contact botanic garden ranger Kat Lord.
