OPINION: People say to me, "if New Zealand's native plants were only more interesting, I'd plant more of them."

Which translates as, "if our native plants had bigger and more colourful flowers, I would plant them."

But if take the time to learn about the incredible evolution of our native plants, I guarantee you'll realise that our natives are more amazing than any exotic you can name. Plus they provide everything our native birds need to thrive.

That's because our birds and plants evolved together. In fact it is the fault of native birds that our native plants aren't as floriferous as we would like!

MATTHEW CATTIN/FAIRFAX MEDIA Kererū perches on nīkau tree.

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People also often say they plant exotics because their flowers 'bring in birds'. They seem to too easily forget that our birds and our plants provided all that was needed for each other's survival before humankind set foot on this land.

We do not need to plant foreign plant species to feed our birds. We simply need to plant more – a lot more – of our own amazing native flora. I am sad to say that there are now more weed species than native plant species found in New Zealand.

CHRISTINE CORNEGE/STUFF Tūī play in a kōwhai tree in Cambridge.

If you don't plant natives because you don't like the way they look, I encourage you to look at them again. Many gardeners I meet are inexperienced with our native plants, and have not seen what can be done with them. Others feel they are hard to grow, or simply, do not know them so don't buy them.

Yet, our native plants have texture, look good, are there in the winter… and yes, some of them offer flowers too!

I am not saying you cannot have your exotic flowering plants; nor that you should have only native plants in your garden. But I am saying that native plants provide our birds with what they need – and support all our other fauna too.

BUT WHY DON'T OUR NATIVES HAVE MORE COLOURFUL FLOWERS?

In the evolutionary sense, New Zealand is a young country. There has not really been time for the close associations that can form between a plant and its pollinator – and the often-fancy flowers that follow elsewhere in the world.

Pollination is the first step in the sexual reproductive process in plants, it is the pollen (male part with sperm inside) coming in contact with the stigma of the female part.

Self-pollination is when the egg is fertilised by its own pollen or one from a flower on the same plant. This is great if you wanted to reproduce quickly, like many of our shortlived weed species. But, there is no genetic diversity, so there is less likelihood that the species will have offspring capable of being able to adapt to changes in its environment and/or be resistant to certain pests and diseases.

Cross-pollination on the other hand leads to genetic diversity, the pollen coming from a genetically different plant of the same species. This is all about survival. We think that all plants look identical but an individual species is as variable as we are as Homo sapiens. We are all so different and so are our plants!

To ensure cross-pollination, plants need a means of transferring the pollen from one plant to another. Some, such as our native beech trees, podocarps, all our grasses and even our coprosmas, are lazy and use the airwaves, letting loose vast quantities. Such plants do not require fancy flowers as there is nothing to attract.

All the other plants use animals. To get the animals to come, the plant needs to provide an incentive, and like most animals food is often the winner on the day. For most it is nectar but for some it will be pollen or even both.

In general, the larger the flower, the larger the animal undertaking the pollinating. No matter the size of the pollinator it is costing the plant energy to make the product; the bigger the pollinator the greater the demands on the plant. This energy could be being used to grow, defend themselves from pests and diseases, take up nutrients from the soil and more. There is a cost to producing a fancy flower but they will do it for reproduction.

Here, very few native plants produce large flowers because the nectar feeders we have are small. They include our native bees and wasps (both small when compared to relatives elsewhere in the world), moths and our few butterflies. Their proboscises were of equally small stature. Other nectar-feeding pollinators here are flies, wētā, bats - and of course our native birds.

But our native birds are mainly not obligate nectar feeders (as in only feed on nectar). They also dine on other things as well, such as insects, fruit and / or foliage. So only about 8 per cent of our native plant species are pollinated by birds - and some of those are happy for an insect to do it too.

So really it is not our plants' fault that their flowers are as they are - it is the pollintaors' fault! Of which our native are but one type.

I would love to see gardeners grow more native plants. We are the ones who can bring our country's flora – and consequently its fauna – back to life. Be sure to ask at your garden centre for any species you cannot find so they can let the nurseries know there is a demand. If they do not know, they will not try to produce them.



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