New Zealand’s plants are unique, having evolved in isolation for millions of years. Did you know that 80% of our trees, ferns and flowering plants are found only in New Zealand and nowhere else in the world? Many of our plants have evolved distinctive features that make them interesting additions in the landscape. Why not incorporate some of these special features and unusual growth forms into your garden? Find out more about growing native plants at your place.
What makes our plants special
New Zealand’s plants are unique because:
- New Zealand has been isolated from the rest of the world for about 80 million years – plenty of time for plants to evolve in their own special way.
- There are no native browsing mammals – our plants evolved to being browsed by birds (particularly moa) and insects.
- We have a relatively mild, wet climate – most of our species are evergreen and our forest structures more closely resemble tropical forests than temperate counterparts in the Northern Hemisphere.
This has resulted in a high instance of unusual characteristics, including:
- Different juvenile and adult foliage – ‘Heteroblasty’
- Tangly interlacing branches – ‘Divarication’
- Separate male and female flowers – ‘Dioecious’.
Find out what these terms mean and more about these characteristics below.
Scientists call the condition of having very distinct juvenile and adult forms ‘heteroblasty’. New Zealand has a high percentage of heteroblastic species. The juvenile form can look so different from the adult that they look like completely different species. The lancewood is probably the most well known heteroblastic plant in New Zealand.
There is no general agreement about why certain plant species do this, but scientists have several competing theories. One theory suggests that it evolved as a response to moa browsing, and that once trees grew above moa height, they no longer needed the special defences of their juvenile leaves.
Divaricating species have small leaves and wide-angled branches that interlace and give a tangled appearance. These species tend to look like a chaotic tangle of small branches. Many of the small-leaved Coprosma species are divaricating.
Many heteroblastic species have a divaricating juvenile form that has sharply angled interlacing branches and small leaves. Then as the tree matures it takes on a more traditional tree shape with much larger leaves. Examples include kaikomako, kowhai, matai and lowland ribbonwood.
Divarication occurs across many plant families and can be found in some genera or species within that family, but not necessarily all. Current theories to explain the advantages of divarification include:
- It is a defence mechanism against Moa browsing.
- It is an advantage in dry, cold, windy environments and may have evolved as a common form during the last ice age.
- It forms an ideal habitat for lizards to live in, where they are protected from predators. The lizards in turn eat the fruit and disperse the seeds.
Divaricating plants add an interesting texture to gardens. Why not give them a try at your place?
Another interesting feature of New Zealand plants is the high number of species that have separate male and female plants. While this is the norm in the animal kingdom, it is unusual for plants. Approximately 12-13% of our flora are dioecious. This is important to know when planting natives in your garden. For example, you may be waiting year after year for your Coprosma shrub to produce berries, but never get them –because you have a male plant that produces only pollen when it flowers.
Making a ‘Southland’ garden
When incorporating some of Southland’s native species into your garden, why not try:
- Heteroblastic species, such as lancewood, kaikomako, lowland ribbonwood and marbleleaf.
- Divaricating species, such a mingimingi and weeping mapou.
- Cabbage trees – New Zealand icons
- Flaxes – lowland and smaller mountain flax
- Red tussock – give great texture
- Pink-flowered native brooms.
If you’re feeling adventurous, why not try growing Fragrant Tree Daisy (Olearia fragrantissima) or Hectors Tree Daisy (Olearia hectorii) – two of Southland’s rare and special plants that are threatened in the wild. They are deciduous with highly scented flowers. Come and see examples in our threatened plants garden.
There are also examples of many different native trees shrubs and flowers that you may not have seen before in our native garden. Come and have a look.
Find out more about what to plant to attract native birds to your garden.
Find out more
Contact us for more information about planting native plants at your place.