Native Planting and Biodiversity Trends in New Zealand Gardens

Biodiversity is the variety of all living things in a place or ecosystem, such as forests, oceans, rivers, wetlands and even suburban back yards. In this article, Rebecca Hughes from Blue Mountain Nurseries explains how landscapers can make a positive impact to biodiversity with their plant choices.

Clean, stable environments with plenty of native biodiversity can produce healthy ecosystems. A healthy ecosystem provides a range of benefits, such as nutrient-filled soils, clean water, oxygenated air, storage of carbon, reduction of climate change and waste management.

Home gardens are becoming an increasingly important part of biodiversity conservation in New Zealand. Rather than focusing on highly manicured landscapes, many homeowners are choosing to create gardens or parts of gardens as a functioning ecosystem that provide food, shelter and movement corridors for native birds, insects, lizards and other wildlife.

Even a small suburban garden can have a significant impact in improving biodiversity by:

• Planting a mix of species that flower across different seasons.

• Providing water for birds and insects.

• Leaving some leaf litter and fallen branches as habitats.

• Avoiding pesticides where possible.

• Controlling invasive weeds.

• Planting densely to create shelter and reduce bare ground.

• Helping reconnect fragmented urban habitats.

PLANTING FOR NATIVE BIODIVERSITY

In the landscape setting, choose native plants that provide food and shelter for birds, insects and lizards. Food sources available through the seasons include pollen, seeds, fruit, nectar and insects.

Species like harakeke (flax), kōwhai and mingimingi not only look beautiful but also support local biodiversity through the provision of nectar and berries. Kererū (wood pigeon) eat the fruit and leaves of nīkau, miro, cabbage tree, kōwhai and māhoe.

Plant species that attract bellbirds include kōwhai and flax, providing a good source of nectar from late winter through to summer. Planting coprosmas, five-finger, broadleaf, cabbage trees and kahikatea also provides fruit that is valuable in autumn when nectar supply is scarce.

Key biodiversity trends

1. Native species over traditional ornamentals

Plants such as kōwhai, harakeke, koromiko, Carex testacea and mānuka are increasingly favoured because they are adapted to local conditions, generally require less irrigation once established, and provide nectar, fruit or shelter for native wildlife such as tūī and bellbirds, native bees, butterflies and beneficial insects.

2. Gardens designed for biodiversity

Rather than focusing only on flowers, gardeners are creating layered habitats with:

• Canopy trees

• Flowering shrubs

• Grasses and sedges

• Leaf litter and logs

• Groundcovers

• Year-round nectar sources

3. Regional planting

There’s growing emphasis on using ecosourced native plants – species naturally occurring in the local area because they are often better adapted to local soils and climate and support local ecosystems more effectively.

4. Less lawn, more planting

Many homeowners are reducing large lawns in favour of native borders, rain gardens, edible gardens integrated with native species and densely planted mixed beds.

This creates more habitats while reducing the need for mowing and excessive water use.

Native plants for biodiversity

• Sophora 'Milligold' – A compact, pendulous tree with yellow spring flowers that attract nectar-feeding bellbirds and tūī. Evergreen.

• Austroderia richardii (Cortaderia richardii) – Hardy native grass with feather-like flowers from November to January. Height: 2m.

• Astelia chathamica – Silver-green foliage with spring flowers and orange berries on female plants. Height: 1m.

• Corokia cotoneaster – Hardy, low-growing native shrub with fine branching and small leaves. Height: 1m.

• Podocarpus totara 'Wanaka Black' – Upright totara ideal for hedging, with green summer foliage turning dark burgundy-black in winter. Height: 3m.

• Carex testacea – Bronze and green native grass, best planted in clumps.

• Corokia virgata 'Frosted Chocolate' – Bronze-coloured native suited to sunny positions. Height: 1.5m.

• Sophora molloyi 'Early Gold' – Compact native with early yellow flowers. Height: 1m.

• Hebe 'Snow Cap' – Large-leaved native with white flower spikes. Height: 1.5m.

• Sophora microphylla – A large shrub or small tree producing masses of rich yellow flowers. Height: 2.5m.

  
  

Rebecca Hughes holds a BSc (Hons) in Botany and has previously been National Training Manager for the Horticulture Industry Training Organisation (ITO) and General Manager for the Community Support Services ITO.

She is currently co-director of Blue Mountain Nurseries, a family-run wholesale and retail nursery established in Tapanui in 1932.