Weeds were not part of the original equation.
When designing the trial, the focus was squarely on a straight comparison of the establishment rates of open-ground, potted or bagged, and root trainer –raised plants. Comparative resilience to the impact of competing weeds, strictly speaking, should have been left to a subsequent, or additional, trial.
In the event, some early preferences by the land owner and planting contractor, and then the weeds themselves, determined that the trial would be a real world one—the plants being subjected to a high degree of competition from weeds. Strong competition from weeds, of course, is not an uncommon situation in restoration plantings.
The plants on three of the four sites were fully released in December 2008, but by that time, the smaller plants were difficult to discern amongst the competing grasses. The root trainer –raised toetoe were particularly difficult to locate, occasionally consisting of only two or three slender, light-deprived leaves. In spite of this, on the Silverdale river flat site, every individual was accounted for.
Weed growth on the steep hillside site at Silverdale was judged to not threaten the trial plants, which accordingly were not released.
Releasing was done by two methods:
- 1 Mechanical—weed eater and hand sickle
- 2 Chemical—glyphosate-based herbicide.
Mechanical methods were used to release the harakeke, tï köuka and toetoe. These monocots are susceptible to the herbicides that can otherwise be used to control weeds and grasses competing with woody species. While there are techniques that can be used to minimise damage to monocots—harakeke is thought by some to be comparatively resistant—the risk to the trial were considered to be too great. A powerful weed eater with tungsten wire –filled cutting cord was used to clear the bulk of the competing vegetation; a hand sickle was used the clear the remaining vegetation from around the trial plants.
Eleven months on, as this report is written, the need for releasing is beginning to be assessed. Although seasonal weed growth has yet to peak, it is clear that most of the plants will survive the competition. It is equally apparent that the growth of most trial plants will be less than optimal, if there is no intervention.
In the next section, the extensive measurements taken will be discussed in detail, but the gamble to use minimal releasing appears to have paid off, in the pattern that is emerging.
Next section Transplantation Shock
Previous section Toetoe Gets to Play
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Part of a hope-based network restoring and enjoying the Mahurangi
Editor Cimino Cole
Deadline for submissions Midnight 31 May
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Not perfect but a Field day and a half
The Mahurangi Action Plan –inspired Open-Ground and
The War Go On: Potted (foreground) and open-ground (middle) harakeke established 17 months at Sandspit Road are safe from smothering. The root trainer –raised plants that have survived, one which Cimino kneels before, have suffered badly in their competition with weeds and are barely taller when they left the nursery. Photography Majorlook Productions