Invasive Species Removal in Dunedin

Invasive trees and pest plants are a significant problem across Dunedin and the wider Otago region, threatening native biodiversity, destabilising hillsides, and reducing the ecological value of properties. Professional removal requires more than just cutting — effective control means understanding each species' biology and preventing regrowth or seed spread during and after removal.

Common Invasive Tree Species in Dunedin and Otago

Several tree species have been identified as significant environmental weeds in the Otago region:

Crack willow (Salix fragilis) — widespread along Dunedin waterways, aggressive root systems damage drainage infrastructure and crowd out native riparian species
Sycamore (Acer pseudoplatanus) — prolific seeder that self-establishes readily in urban bush remnants and displaces native regeneration
Elderberry (Sambucus nigra) — dense stands in disturbed areas and along waterways, shades out native groundcover and seedlings
Alder (Alnus glutinosa) — naturalised along many Otago streams, alters soil chemistry and suppresses native plantings
Darwin's barberry (Berberis darwinii) — thorny shrub that spreads rapidly into bush margins, listed as a regional pest plant
Gorse (Ulex europaeus) — a significant fire risk on dry hillsides and a major weed problem on farmland boundaries

Our Removal and Control Methods

Effective invasive species removal is species-specific. We use a combination of techniques depending on the plant, site, and environmental sensitivity:

Cut and stump treat — felling or cutting followed by immediate herbicide application to the cut surface to prevent regrowth. The most common method for established trees and shrubs.
Drill and inject — herbicide injected directly into the trunk without felling, suitable for large trees where felling is impractical or the debris would cause problems
Basal bark treatment — herbicide applied to the lower trunk, effective for multi-stemmed shrubs
Full physical removal — excavation of roots and stump, essential for species with strong suckering or resprouting capability

Environmentally Responsible Practice

Invasive removal near waterways, native bush remnants, or in ecologically sensitive areas requires careful planning to avoid spread during the removal process. We select methods that minimise disturbance, control debris appropriately (many invasive species will resprout from cuttings left on the ground), and can recommend native replacement plantings to help restore the site after removal.