Expressway more than just tarseal
We don’t build highways like we used to.
Forty years ago it was all about laying tarseal but projects such the Waikato Expressway have seen millions of native plants put into the ground.
Landscaping business Natural Habitats has planted out both the Huntly and Rangiriri sections of the expressway. It also has the contract for the under-construction section that’ll bypass Hamilton.
Over 1.3 million plants were ecosourced, propagated and raised before being planted in the 15.5km Huntly stretch.
Company founder Graham Cleary said the project takes a massive amount of planning as every plant is sourced from the area.
‘‘Even though a really basic plant like manuka or tea tree grows basically all over the country, every area is slightly different so it is basically trying to preserve the unique genetic makeup of the plants in the area.’’
On the Huntly project there were more than 1.3 million seeds collected because there is a fair amount of failure.
‘‘Also some native seeds are so small you don’t individually count them you just do it by weight. We then test the seeds’ viability, and then we propagate from there.’’
The company also takes the GPS location of all the mother plants. ‘‘That’s just to ensure if someone says, hey, tell me where that plant came from, we can give them the GPS location which they can go and check it’s there and it’s undamaged.’’
The plants aren’t just to make the area look beautiful – they can have a number of benefits. ‘‘It goes right back to when the road is being designed and in certain areas it will be obviously erosion prone, or they might be used for water treatment. Like as water washes off the road it’s pretty toxic water and so it has to flow throughout wetlands.
‘‘Propagation for very quick growing plants like grasses and things is done every year. So we would have collected the seeds then every year we would progressively propagate more and plant them out in the planting season which is basically the winter.
‘‘The native trees tend to be really slow growing, so we have to propagate those really early and then grow them over a few years before they go outside.’’