Twiggy Tree Daisy
Olearia bullata
The Twiggy Tree Daisy (scientific name: Olearia bullata ) is a hardy and distinctive divaricating shrub endemic to New Zealand. Primarily found in the South Island, it is a master of adaptation, thriving in the damp, often challenging environments of wetlands and subalpine shrublands. Characterized by its dense, interlacing reddish twigs and small, deeply wrinkled leaves, it exhibits the classic "divaricating" habit so unique to the New Zealand flora. This guide explores its fascinating physical features, its important role as a host for native biodiversity, and how to successfully incorporate this resilient native into Native Shrubs .
Plant Description
Olearia bullata is an evergreen, bushy shrub that typically grows to a height of about 2 to 4 metres. It is defined by its divaricating growth habit, featuring wide-angled, reddish-brown twigs that interlace to form a dense, protective structure. The foliage consists of very small, narrow, brownish-green leaves that are deeply "bullate" or wrinkled-a feature from which it derives its specific name. The leaf margins are often rolled downwards, and the undersides are covered in a soft white or grey tomentum. In summer, the shrub produces clusters of small white daisy flowers, which are relatively inconspicuous but add to the plant's overall character. These are followed by fluffy, wind-dispersed seeds. The bark is typically greyish and somewhat flaky, adding to the plant's rugged, mountain-hewn appearance.
Quick Facts
| Scientific Name | Olearia bullata |
|---|---|
| Height | 2-4 metres |
| Spread | 1.5-3 metres |
| Water Needs | Moderate to High (Prefers damp) |
| Light | Full Sun to Partial Shade |
| Frost Tolerance | High (Fully hardy) |
| Salt Tolerance | Moderate |
| Growth Rate | Medium |
| Lifespan | Perennial (Long-lived) |
Climate Best Suited to
The Twiggy Tree Daisy is a remarkably hardy species, perfectly adapted to the cool, moist, and often breezy climates of the South Island. It is a facultative wetland species, meaning it thrives in damp ground and can handle high rainfall. It is exceptionally frost-hardy and can withstand the heavy snow and cold winters of inland montane basins. While it can grow in warmer regions, it performs best where the air remains relatively cool and humid. It is not suited to extremely dry, hot, or sheltered northern microclimates where stagnant air might encourage rot within its dense branch network.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Christchurch | Excellent |
| Dunedin | Excellent |
| Invercargill | Excellent |
| Wellington | Good |
| Auckland | Moderate (Requires a moist, airy spot) |
Plant Habitat
Naturally, Olearia bullata is found in wetland margins and damp upland shrublands throughout the South Island. It is a frequent colonizer of areas that were formerly forested, particularly in the eastern and central regions. It typically grows from sea level up to around 600 metres, though it can occasionally be found higher in suitable microclimates. It is often found growing in the company of other small-leaved natives such as Mānuka, Coprosma propinqua, and C. rugosa. It is well-adapted to the heavy, often loamy or peaty soils of marshy river terraces and intermontane basins.
Plant Conservation
The Twiggy Tree Daisy is currently classified as "Not Threatened" in New Zealand. Its broad distribution and ability to handle disturbed, damp environments have helped it remain common in the wild. However, its value to conservation is immense; it serves as a critical host plant for a vast array of native biodiversity. It provides habitat for numerous spiders, insects, and snails, and its complex branch structure supports diverse communities of mosses, lichens, and algae. Notably, this and related small-leaved Olearias provide food for the larvae of up to 41 species of New Zealand moths, making it a foundation species for local ecosystems.
Growing Requirements
Soil Requirements
Very adaptable but thrives in soils that remain consistently damp. Tolerates heavy loam.
- Moisture-retentive soil preferred
- Tolerates heavy or sandy substrate
- Accepts a wide range of pH
Light Requirements
Best in full sun or partial shade. Full sun encourages a tighter, more architectural form.
- Full sun preferred
- Partial shade tolerated
- Maintain good air movement
Water Requirements
Requires consistent moisture. Does not like to dry out completely for long periods.
- Regular watering in dry spells
- Thrives in high rainfall
- Benefit from natural rainfall
Planting Guide
When planting Olearia bullata , choose a spot that stays relatively moist, such as a gully margin, the edge of a pond, or a damp corner of the garden. Dig a hole twice as wide as the root ball and enrich it with a little compost if the soil is particularly poor. Plant at the same depth as it was in its container. Early spring is the ideal time for planting to allow the roots to establish before the heat of summer. While it is wind-tolerant, providing some initial shelter in very exposed sites will help the young plant develop its characteristic interlacing form. Mulching is generally not necessary if the soil is naturally damp, but a light layer of bark can help retain moisture in drier sites.
Ecological Role
The Twiggy Tree Daisy is an ecological powerhouse. Its complex, divaricating branch structure acts as a dense protective thicket, providing safe nesting and refuge for small native birds and lizards. It is a critical host for native invertebrates; the interlacing twigs trap debris and moisture, creating micro-environments for snails, millipedes, and worms. Most importantly, it is a primary host for New Zealand moths, with its foliage supporting the larvae of dozens of species. By hosting a rich community of lichens and mosses on its bark, it further contributes to the botanical and biological complexity of the New Zealand shrubland ecosystem.
Uses & Significance
Garden Uses
A fantastic textural plant for structural interest or informal hedging in damp sites.
- Excellent structural focal point
- Hardy informal screen or hedge
- Perfect for native wetland plantings
A key member of the unique New Zealand divaricating shrub community.
- Symbolic of New Zealand's "grey scrub"
- Of high value for biodiversity-focused gardens
- Historically significant for native moth conservation
Ecological Value
Supports a vast community of native invertebrates and mountain biodiversity.
- Primary host for up to 41 moth species
- Habitat for snails, spiders, and lizards
- Stabilizes damp soils and wetland margins
Cultural Significance
While specific records are limited for this species, Olearia bullata sits within a wider native plant tradition valued for its ecological role and local stewardship.
Landscaping Uses
In landscaping, Olearia bullata is valued for its unique architectural silhouette and textural contrast. Its reddish-brown interlacing stems provide a sophisticated "grey scrub" look that works well in modern, ecological garden designs. It is particularly effective when planted in groups to create a dense, wiry screen or used as a structural element along water features. The fine-textured foliage contrasts beautifully with larger-leaved natives like Phormium (Flax) or Griselinia. Because it can handle wind and frost, it is an excellent choice for creating structure in challenging, high-country or coastal landscapes.
Seasonal Care Calendar
Spring
As new growth appears, focus on root establishment.
- The best time for relocation or new planting
- Monitor soil moisture as growth starts
- Check for any aggressive weeds in the centre
Summer
The peak growing and subtle flowering period.
- Water deeply during prolonged dry spells
- Enjoy the small white flowers
- Watch for seed development in late summer
Autumn
Growth slows and the plant prepares for dormancy.
- Collect seeds for propagation
- Reduce watering as rainfall increases
- Ensure good air flow through the branches
Winter
The plant is dormant. The best time for structural work.
- Perform light pruning to remove dead wood
- Remove any fallen leaves trapped in branches
- Fully frost hardy; no protection required
When to Prune and How Much
Olearia bullata responds well to light pruning, which helps maintain its dense habit.
- Remove any dead or damaged branches in early winter
- Lightly tip-trim to encourage bushier growth in spring
- Clear out the centre occasionally to improve air circulation
Always use sharp, sterilized snips. Avoid heavy, radical pruning as this can stress the plant and disrupt its natural architectural form. The goal should be to tidy the shrub and maintain its vibrant reddish-brown twig colour and interlacing habit.
How to Grow Twiggy Tree Daisy ( Olearia bullata )
Growing the Twiggy Tree Daisy ( Olearia bullata ) is a straightforward process, making it an excellent choice for anyone looking to support New Zealand's native biodiversity. The most important factor for success is ensuring the plant has enough moisture. While it is a tough survivor, it truly thrives in ground that remains damp year-round. If you are planting it in a drier garden, choose a spot that doesn't get baked in the afternoon sun and consider using a thick mulch to keep the roots cool. Traditionally, native plant enthusiasts have found that this species doesn't require much fertiliser; a simple application of compost or sheep pellets in the spring is more than enough. One of the greatest rewards of growing Olearia bullata is the life it brings to the garden. Within a few years, you will likely notice an increase in native moths and small spiders, all of which use the dense twigs as their home. It is a fantastic, low-maintenance plant for creating a wild, natural feel in any New Zealand landscape.
From Seed
Seeds are easy to grow if sown while fresh.
- Collect fluffy seeds in late summer or autumn.
- Sow on the surface of a seed-raising mix.
- Lightly cover with a fine layer of grit or vermiculite.
- Keep moist and place in a cool, bright spot.
Germination is usually reliable and occurs in the following spring.
From Cuttings
Semi-hardwood cuttings are the most common propagation method.
- Take 10-15 centimetre cuttings in late autumn or winter.
- Remove the lower leaves and dip in a rooting hormone.
- Insert into a mix of sharp sand and peat.
- Keep in a cool, humid, and shaded environment until roots form.
Additional Methods
Relocation of young self-sown seedlings is often possible.
- Look for small, wiry seedlings near mature plants in spring.
- Carefully lift with a good amount of surrounding soil.
- Replant immediately and water well until established.
Pests & Diseases
Olearia bullata is generally robust and suffers from few serious pests or diseases. Its biggest enemy is stagnant, overly humid conditions, which can lead to fungal die-back or mildews within the dense branch structure. Ensure the site has good air movement. While it hosts many insects, most are part of its natural ecosystem and do not harm the plant. Slugs and snails may occasionally graze on young shoots in spring. If the plant is grown in a container, monitor for root mealybug.
Bonus Tip
To see the full potential of this plant as a biodiversity host, avoid using any broad-spectrum insecticides in your garden. The complex "micro-world" that lives within the twigs of Olearia bullata is one of its most fascinating features and a major contribution to your local ecosystem.
Related Plants
Explore other native plants that share similar characteristics or habitats with Twiggy Tree Daisy ( Olearia bullata ), offering further insights into New Zealand's diverse flora. These related species provide context and opportunities for complementary planting in your garden.
