|Our Environment: Issue 20 Spring 1999|
Sowing Seeds Of The Past
This years clusters of white cabbage tree flowers looked particularly attractive to nurseryman Joe Cartman. Charged with finding local, eco-sourced native seeds for Christchurch City Council parks, waterways and reserves, Joe had started to feel increasingly anxious. While scouring the Port Hills during the past three years he had found plenty of cabbage trees and even lots of flowers. No seeds, though, to fill annual orders for about 4000 cabbage trees.
"I think I visited every cabbage tree in the Port Hills," says Joe recalling his frustrating search and dwindling seed stocks. This year though its business as usual for Joe who is supervisor at the Councils two nurseries at Smith Street and Gardiners Road. He gathered as many seeds as he could lay his hands on just in case there are a few more barren years ahead. Obtaining the seeds poses its own challenges.
Because native varieties planted by the City Council should be from local genetic material uncontaminated by imported strains, Joe gets his seed stock from cabbage trees growing naturally, well away from gardens. That often means scaling rocky outcrops high in the Port Hills, armed with four metre "nippers" to cut the seed-bearing flowers.
During seed quests between December and May, Joe can also be found searching Christchurchs wetlands, sand dunes, river banks and other pockets of native vegetation for seeds to fill orders placed by the City Councils Water Services, Parks and City Streets units. Over 400 native flowering plants grow wild within Christchurch. Joe says a surprising number of remnants survive in the City but every time he does his rounds one or two more have disappeared.
Berries are "squished", separated in water, dried, then stored in the refrigerator. Raupo seeds are the only really difficult ones to extract, says Joe. He sprays the fluffy flowers to kill off caterpillars then puts the heads in seed boxes, fluff and all. Potting begins at the end of September and plants are sent out as soon as they reach the required size. Flax (Phormium tenax) is the most sought after species, with orders for up to 12,000 plants each year.
Although there is a general Council preference for native, locally-sourced plants, Joe also grows many North island natives, usually for their colour or other special characteristics. Most are grown in containers at the two and a half hectare Smith Street nursery. Small orders and most exotic plants are contracted out because of space constraints. Larger species such as red oaks, ash, beech and liquidambas are grown in open ground at the Councils 11 ha Gardiners Road nursery.
Joe has noticed a radical change in planting philosophy during his 24 years working for the Council. Initially most plants grown were exotics. These days more than half are native, earmarked for ongoing planting programmes, particularly in Christchurch 650 parks and reserves and along the citys 400 km of waterways. Wairarapa, Nottingham and Avoca Valley streams and Sheldon Park are this seasons major planting sites.
At the same time, extensive restoration planting is being carried out by the Department of Conservation, Turning Point 2000 and other project groups. The Council is also encouraging residents to incorporate native plants in landscaping plans. Useful advice includes a Streamside Planting Guide, explaining what to plant and how to maintain native plants along freshwater streams in Christchurch.
It was developed as part of the Council-driven waterway enhancement programme which aims to: protect natural areas restore native habitat create green linkages restore waterways for peoples enjoyment and sense of history; enhance ecosystems for birds, fish, lizards and insects
The number of native birds on the Avon River has almost doubled since 1993, according to a survey by ornithologist Andrew Crossland. Restoration planting and better management of the Citys waterways and wetlands has been credited for the increase. Ecology, landscape, culture, heritage, recreation and drainage are the six values which underpin the Councils management approach.
The Council has a mandate not only to protect threatened remnants of our biodiversity but to enhance, expand and restore them to mitigate past effects of serious losses, says botanist Dr Colin Meurk, who works for the City Council and Landcare Research. Wetland restoration and enhancement is a logical focus for Christchurch, mostly flat and, in pre-European times, covered with large areas of swamp.
Many city streams and riverbanks have been transformed by attractive native planting, much more sustainable ecologically and economically than the boarded or concrete sides that used to flank many of them. Parks have also been primary targets for restoration planting. Selection of other sites is often fortuitous, depending on what land is available at the time, says Colin Meurk.
He is not deterred by sometimes vehement criticism that Christchurch is undermining its Garden city image. "The moment youre involved in changing the landscape in any way you get opposition."
While appreciating the English image, Colin Meurk says plants are much more appealing in their own natural environment than "our attempts to create a pale imitation of the real thing". Worse, exotics such as crack willow or yellow flag iris spread quickly, crowding out local species and upsetting the local ecological balance.
"If we want to do something unique we should be making our indigenous vegetation much more visible to ourselves and our visitors," he says. "Every place has an obligation to look after things that do not occur elsewhere. Weve signed international conventions guaranteeing that we will do so."
Joe Cartman sidesteps the natives versus exotics debate, saying the two profitable nursery operations he supervises grow to order. However he believes theres room for both natives and exotics. "Its a matter of whats appropriate for the site." Joe also supports the emphasis on locally-sourced native plants. After all they are proven survivors, able to cope with Christchurchs cold winters and dry summers.
He finds his job satisfying. "Its quite a dramatic thing putting 230,000 plants out there in the City every year. What Im doing now is going to have a marked impact. Its going to be there long after Im gone,"
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