Wetlands
So you want to get rid of your weeds on your wetland?
Iseki tractor and rotary slasher. I push my way into the blackberry in low ratio without the slasher running. Once a 2 metre gap is pushed through I gradually chew up the cover with the slasher. After several weeks it will die off and can be made into a serviceable track
When we first took over Pateke Lagoons we were confronted with thirty acres of wetland almost completely covered by blackberry and muelenbechia. Muelenbechia is a native creeper that is usually controlled by other plants in a forest setting. However it had grown rampant and unattended which led to it covering totara trees to ten metres. It was only after our first summer here that we realised that we had many areas of ferns, manuka and mingimingi underneath the creeper. As well as this the only areas that remained unaffected were infested with blackberry. Some of these patches were up to 200m long by 30m wide and well over four metres high. Here is what we have done.
Muelenbechia
The best approach is to get inside the creeper and cut its roots that surround important trees and shrubs as close to the ground as possible. The roots of this creeper can be as much as 40mm thick so it take a fair bit of cutting. Dab Tordon onto the roots as quickly as you can and wait for the freed creeper to die off and fall off the trees. This will take around six months but will have the effect of making it much easier to spray the rest of the infested area whilst still protecting your trees.
For spray we found that Grazon was far and away the best as it did not effect the flax or the carax which is the predominant vegetation on the wetland.
After three years of hard labour we had cut tracks to get at all the wetland and sprayed the creeper into submission. What little is left is welcome as it is easy to control if it looks like getting out of hand.
The effect has been miraculous. The flax that had given up and collapsed for want of light suddenly came to life and after three years was back up to around four metres high. Silver fern, mamaku and cabbage trees have taken on a new lease of life.
Bird life has proliferated throughout the wetland areas due to easier access for the waterfowl to grazing areas being made accessible. By the same token it has been easier for the predators as well so we have to make sure the freed-up areas have well maintained tracks so we can maintain an active trapping programme.
We, mostly Ady in reality, have planted several thousand trees and shrubs native to this wetland and we simply have to ensure the muelenbechia is eradicated to make this very considerable investment worthwhile.
Blackberry
There are a lot of myths about blackberry. One of them is that it can be controlled by grazing. That might well be right for goats who simply love the stuff. However goats and wetlands do not mix at all, as they will eat everything else first! We have noted how cattle will suck at the flax and push through wetlands pogging up the ground and reintroducing weeds throughout.
For us it was different. We have fenced, and sprayed relentlesly for nearly ten years. We are winning.
We have a covenenant with QEII National Trust, which means no grazing in the wetland, and a management plan which includes getting rid of pest infestations. Once the wetland was fenced we noted that the flax and sedges really started to grow. We also noticed that the blackberry continued to prosper.
We repeated the process as for muelenbechia, including cutting tracks in the late autumn and keeping them open throughout the winter if the ground was solid enough.
We find that the best time to attack blackberry is in October. By then the green leaves are in rude good health, and the ground will be solid enough to take the tractor again. Caution however, if the area to be sprayed is close to breeding areas, as they will be affected badly. Leave these areas until February when the waterfowl will all be flying, and the dragonflies have finished their hatchings.
We have a laminated map of the property on which we mark the area of infestation for the next campaign in the war on weeds. I also spray paint the edge of the new track so I can get back easily. Track cutting is a slow process in blackberry as you have to pick away at it very slowly with tractor and rotary slasher. I can usually do about three metres an hour. It is a bit like being in a tunnel but by moving back and forth across the face you can usually make a two metre track without getting too cut up in the process. You will however be bitten by every flying bug that blackberry shrubery supports.
If you are fortunate enough to have spray contractors they will really appreciate your tracks, and it will cost you a lot less money. It is helpful for the follow-up spraying that you will have to do for another four years if you are serious about getting rid of blackberry. It is also very satisfying to go through all your tracks to mark progress. I will tell you one thing. You will need to keep the tracks open for at least four years to make sure you have won the battle. As for the war? Maybe never, sadly.
Once you have finished at your place it is worthwhile killing off any blackberry in the surrounding area as birds will feed on the blackberry and roost in your flax. The resulting mix of bird shit and blackberry seeds is a heady mixture that flax cannot resist and before you know it you are back at war. You really need the cooperation of your neighbours in this regard.
Recovery of the wetland that has been cleared of blackberry
There is nothing worse than seeing blackberry growing rampant again in an area you thought you had cleared. Put simply, if you do not replace it the blackberry will merely re-infest and destroy your hard hard work. This is demoralising to say the very least. We have found that carax is very good as a replacement. It is reasonably dense and grows to 1.5 metres which will often discourage the blackberry. But the very very very best replacement is a grass called yorkshire fogg. It is dense, matts up nicely, grows like hell to around 700mm, and effectively takes the light away from the blackberry sprouts that will come up from last year's roots that you stupidly thought were dead. I merely walk around gathering handfulls of seeds and disperse them in the newly died-off area. Within weeks it is away and growing, and by next September when the blackberry wants to come away, it has been stifled. Oh Joy! The next in the succession is usually bracken followed by flax. The flax will usually take around two springs to start to recover from the crushing that the blackberry caused to it. After five years you will be hard put to maintain your tractor tracks as the flax will have taken over! This is a good thing as the wetland is recovering.