Tag Archives: Cape Pond Weed

Weeding the stream. Again. An ongoing task.

“Believe me, my young friend, there is nothing – absolutely nothing – half so much worth doing as simply messing about in boats.”

Kenneth Grahame, The Wind in the Willows

I misremembered. I felt sure there was a Wind in the Willows quote about messing about in the muddy waters of a stream but I was wrong. Of course they were messing about in a boat, not mud. When I went searching, there were many other charming quotes from the same book which are gently affirming in a world seemingly gone mad, but I found another escape this week.
img_3982I have been weeding the stream. Yes, hand weeding the stream. I see it is five years since I last got down and dirty in the water, although Mark and Lloyd do a certain amount of ongoing maintenance with the long handled rake. I find it easier to climb right in and scoop by hand or sometimes with a rake. It is very muddy and Mark laughs when I stagger back up from the park but I am way too vain (or self conscious, maybe) to immortalise this by taking a selfie of Muddy Me.

There are both eels and fish in the stream – small fish, mostly mud fish – and I find it deeply unnerving when something smooth and slippery brushes past my bare legs. I wouldn’t be quite so anxious were it not for Mark’s recent encounter with an eel. He was reaching into the water to pull out some blockage when an eel mistook his hand for something else and latched on. There was blood, quite a lot of blood and all of it was Mark’s. Eels are renowned for their backward facing teeth so it is not easy to dislodge them, though I think both the eel and Mark got such a fright that everything went flying. I console myself with the thought that eels are not known for aggressive attacks and it would be bad luck for one to follow up with me so soon after. Just in case, I wear both shoes and gloves as a precaution. I am hoping one will not attack my knees, calves or thighs.  Still, as I reviewed one cleaned area of the stream a few hours later, I was disquieted to see an eel gently swimming along the somewhat bare expanse. But it was a small one and I will not be intimidated.

Clockwise from top left: crocosmia, oxygen weed, wretched Cape Pond Weed, blanket weed and tradescantia

Clockwise from top left: crocosmia, oxygen weed, wretched Cape Pond Weed, blanket weed and tradescantia

But the weeds! We get up close and personal with the weeds that are carried down to us from properties further upstream but the major flood in 2015 has caused us a few more problems than before. Crocosmia, often referred to as montbretia but technically crocosmia x crocosmiiflora, have pretty summer flowers but the huge flood carried the corms far and wide and we are now working on restricting its spread. There is simply too much of it for us to be able to eradicate it and we would get reinfested during the next flood event.

Eradication, however, is the aim with the dreaded Wandering Jew (Tradescantia fluminensis). Mark has spent two decades battling this on our properties but still we get new outbreaks washed down to us. The problem is that every piece that is broken off is capable of growing and it is truly rampant once established. Both the tradescantia and the crocosmia grow alongside the water, rather than in it.

The goal is also to eradicate the oxygen weed and the Cape Pond Weed (Aponogetum distachyum). Mark has succeeded once in eradicating oxygen weed so he was most disappointed when he saw a larger form of it getting established on our place. His theory is that it comes from people emptying their little aquariums into fresh water ways, presumably because they do not wish to euthanise their goldfish and can’t find anyone to give them too. Don’t. Please don’t ever do this. Not only do we not need or want free range goldfish in our waterways, the oxygen weed becomes a choking blanket in slow moving fresh water. We have spent countless hours pulling it out but unless we get every bit, it will grow again. Ditto the Cape Pond Weed, about which I have written several times in the past.

What I call the blanket weed – a mass of very fine filaments – is here to stay but we try to keep it from getting too solid and impeding the flow of water. It is at least easy to rake out. Besides, the aquatic life needs some cover.

We are not perfect. Although we try and dead head our waterside irises and primulas, some of those may have washed downstream. I did at least go to a lot of effort to get rid of the noxious flag iris beside and in the water when we realised what an environmental hazard it is in this country.

In the meantime, there are worse ways to spend a pleasant, mild day than poddling about in the water. Our adult son is returning home from overseas next week and plans to stay for a few weeks. He spent many childhood hours playing with his mates in the ponds and the stream  – boogie boarding up and down and playing bike jumping games into the water. I am wondering at what stage I might suggest to him that it would be a huge help to his Aged Parents if he could turn his attention to scooping or raking the weeds from the deepest sections of the ponds which are beyond my reach. We shall see.

We have lowered the water level to enable major weed removal over the next week or two

We have lowered the water level to enable major weed removal over the next week or two

Advertisements

Our worst weeds

After advocating for wildflowers on our road verges in January, it is perhaps ironic that I follow up with the worst weeds in our garden. All are ornamental garden escapes and none should be liberated to roadsides.

Cape Pond Weed

Cape Pond Weed

There are times Mark has wanted to line up and shoot the former neighbour upstream from us who deliberately planted Cape Pond Weed – also known as water hawthorn, botanically Aponogetum distachyum. Pretty it may be in bloom, but we have been waging war on it for well over a decade. Floods scoured it out upstream but it has made itself right at home in our slow moving sections. We spend countless hours raking it out each summer because it we don’t, it will only take one full season before it covers the entire water surface. Miss one piece and it grows away again at an alarming speed.

Prunus campanulata filled with tui

Prunus campanulata filled with tui

Prunus campanulata ranks amongst our two worst weeds. We are constantly pulling seedlings out, or digging if they have snuck through to a second season. Any older than that, and they require poisoning. Yes I know some folk think we should get rid of all of these but the tui! The tui! And please do not tell me to plant kowhai for the tui instead because they don’t flower at the same time and even our largest kowhai trees cannot sustain the scores of tui that frequent our early blooming Taiwanese cherries. So we continue to deal to the unwanted seedlings on an ongoing basis.

There is hope. Mark has been turning his attention to the sterile campanulatas we have here, because it is the seed that is the problem. His father bred sterile campanulata hybrids – ‘Pink Clouds’, ‘Mimosa’ and ‘Petite Pink’. The last variety is probably not commercially available now which is a pity because it is a true dwarf tree. The problem with all three varieties is that they are candy pink, not the sought after carmine red. But we have a few sterile reds with some possible options which give flower power and nectar for the tui without the curse of seed.

About the bangalow palm's seeding ways...

About the bangalow palm’s seeding ways…

The other shocker – maybe I had better whisper this, given its popularity – is the bangalow palm (Archontophoenix cunninghamiana). Yes it is handsome and reliable but this Aussie import is far too keen to make itself at home. It took a long time for our specimens to start flowering but boy, are they a problem now. Mark tries to cut the seed off as soon as it is visible, but this requires the extension ladder and a pole saw. There is probably not a square metre left in our garden where we have yet to find a germinating bangalow. What is particularly concerning is that in the early stages, they are very difficult to pick apart from seedling nikaus. If you are anywhere near native bush or reserve, this is one plant that you should question having in your garden. Based on our personal experience, we recommend the Queen Palm (Syagrus romanzoffiana) as an alternative.

Mark adds in Cornus capitata, the weedy dogwood. It was favoured by his father who planted it all along one of the road frontages and Mark has been battling it ever since. At least it makes good fire wood.

Fuchsia boliviana performs TOO enthusiastically in our climate

Fuchsia boliviana performs TOO enthusiastically in our climate

We have reviewed pretty Fuchsia boliviana. We acquired it before it appeared on the National Plant Pest Accord but never moved it into the garden. Thank goodness. In the wilds of the “plant out” area, where some specimens can languish for years while waiting for the right spot to be found, it grew far too vigorously and the carpet of seedlings rang loud alarm bells. It is another of those plants where a sterile form would be advantageous because it flowers for months on end, is showy and has attractive foliage.

Dare I mention the wonderfully fragrant Himalayan Daphne bholua? It is not in the same league as the previous plants but it has certainly seeded down all round the place here. Not all the seedlings flower, either, which is not to their credit. It is another example of a plant which is highly prized internationally but can become a significant weed in our benign climate.

It can be a mighty fine line between a desirable self-seeder and a weed. Most of the plants mentioned produce berry-like seeds which are then distributed by the birds, particularly the kereru. Plants which only seed down close to the parent are manageable but once our feathered friends are on the loose, it becomes a different matter altogether.

First published in the March issue of NZ Gardener and reprinted here with their permission. 

The battle with the water weeds

We have dropped the water level for me to hand scoop the stream

We have dropped the water level for me to hand scoop the stream

I have been getting really down and dirty this week, hand pulling the weed from our main stream. As this involves wading in mud up to my knees, I emerge looking decidedly worse for the wear and no, you are not going to see a photo of me in this state.

Our main issues are with dreaded oxygen weed, Cape Pond weed and blanket weed. If we didn’t stay on top of them, the entire water surface would disappear below vegetation, which rather defeats the purpose of having a stream in the garden. I asked Mark if he thought our problems were related to farm run-off and excessive nitrogen but he is of the opinion that it has more to do with slow water flow rates, though he felt the build up of mud and silt in our streambed would be extremely fertile. When we get sudden bright green algal bloom, it is an indication of nitrogen being applied on farms upstream.

The worst offenders: Cape pond weed and oxygen weed

The worst offenders: Cape pond weed and oxygen weed

There is something very appealing about a natural stream but they are not without their problems. Offhand, I thought of three gardening colleagues with natural streams. One has problems with flooding in torrential rain. The water cannot get away fast enough so it builds up on his property. One has no problem at all with flooding because their stream is in a deep ravine, maybe 20 metres below the level of their land, but this means it isn’t really a significant garden feature. The third has a picturesque mountain brook to die for, bar two factors. Their land has sufficient natural fall to clear flood waters quickly but the bubbling brook can turn into a torrent that scours everything alongside. This means that they can’t have streamside plantings of any quality. They tried two or three times before giving up, having seen the plants ripped out and carried away. Their second issue is that the water is of high purity so a number of neighbours have water rights granted. Each neighbour has installed their own alkathene pipe at the top of our friends’ garden where the stream enters, running the pipes along the streambed until they exit at their adjoining properties down the bottom. There must be at least five alkathene pipes, both black and garish white, visible in that stream. It is not a good look.

So be careful what you wish for. None of these people, however, have to do what we do and clear the waterway of vegetation every year or two. We eliminated problems with flooding and scouring but our water flow is not sufficient to stop the growth of water weed. Our wonderfully natural looking stream is actually the result of outside expertise and in-house experience coming up with a low tech solution. We control the water where it enters our property by means of a simple weir. In normal conditions, this allows the water to flow equally down two streambeds. One meanders pleasantly through our park while the other is a deeper flood channel girded by stop banks. The two stream beds join up again on the other side of our property so the flow downstream is completely unaffected. When heavy rains cause flooding, a mechanism is triggered which directs all the water down the flood channel. By these simple means, we eliminated flooding, boggy patches and scouring from the park though we do have to manually reset the weir in order to get the water flowing again.

The pond weed is the direct result of having a relatively low flow through the park area, though our stream is such that it never dries up. Oxygen weed is a curse. We had a bad infestation which Mark finally eliminated entirely for some years. He blames the reinfestation on people emptying unwanted goldfish bowls into the stream at the corner by the road. Do not ever do this. The goldfish are most likely to die but the oxygen weed is an invasive menace in slow moving water.

Our other great burden comes from a former neighbour who, as far as Mark is concerned, should be lined up and shot for liberating such an invasive weed. African Cape Pondweed, also known as water hawthorn, (botanically Aponogeton distachyum) is undeniably pretty, with a very long flowering season. Presumably this is why the former neighbour planted it on the margins of his ponds. Because he had no control over the water flow, the inevitable floods scoured it all out of his place but it found a lovely home in our slow moving sections. I don’t know how many hundreds of hours we have spent rooting it out. It is quite good friends with the oxygen weed because it can grow through it and spread its lily pad-like leaves. Between them they have the potential to turn our stream to bog. Native weeds are nowhere near as aggressive.

It is only yours truly who has shed most clothes to get in and hand pull the water weeds this year. Generally this is done by the two men in my gardening life (Mark and Lloyd) who take it in turns to wield the long handled rake and manually haul it all out on to the bank. It is a slow process and pretty hard on their backs. I thought it would be faster and easier to do it by getting in and so it is proving to be. The water is pleasantly warm, the mud even more so on sunny days. I just have to time my mud wrestling because I can’t exactly stop for lunch or a cuppa. Wisecracks about eels are not welcome.

Lloyd at least stays cleaner on the end of the rake but it is harder on the back

Lloyd at least stays cleaner on the end of the rake but it is harder on the back

First published in the Waikato Times and reproduced here with their permission.

In the Garden January 29, 2010

The buds and flowers are edible and it may be pretty but the Cape Pond Weed is dangerously invasive in our waterways and should be shunned at all times

The buds and flowers are edible and it may be pretty but the Cape Pond Weed is dangerously invasive in our waterways and should be shunned at all times

  • If you have hydrangeas full of fresh foliage but precious few or no flowers, the likely problem lies in your winter pruning. Most hydrangeas set flower buds on last season’s growth so if you cut them off at ground level or too low down the stems, you have cut off all the next season’s flower buds. You can not make them flower this season but get some advice before you prune again this coming winter or be less brutal.
  • The end of January usually heralds the time when garden centres start to take delivery of spring bulbs which are sold dry because they are dormant at this time. If you are after anything beyond the usual mass runs, you will need to start haunting your garden centre because anything rare and choice is likely to be available in small numbers only and to sell out quickly.
  • Summer is a good time to give some attention to water gardens and ponds. You are less likely to suffer from hypothermia and the water can start to get pretty green and algae ridden as temperatures rise. If you don’t have fish, you are highly likely to have a breeding ground for mosquitoes unless your water is flowing. We saw a solar powered mini fountain in a friend’s garden in London which was to counter mosquito breeding but don’t know how widely available they are here. The alternative is a plug-in water feature to keep the water moving. A squirt of CRC across the surface of the water will kill the larvae. You may need to seek advice from your garden centre on algae treatments. The simplest water feature of all is a smaller growing water lily plant in a large bowl and a single water lily flower can be a vision of simple perfection. Never but never unleash oxygen weed into flowing streams and shun the African Cape Pond Weed (water hawthorn or Aponogeton distachyum). We know how invasive both are and Mark battles infestations annually in our stream and ponds.
  • If you have an onion crop, the indication that they are ready for harvest is when the stems turn brown and bend over. Once you have dug the onions, they need to dry out for a few days before storing them. Plaiting them or using mesh onion bags is to allow continued air movement so they don’t rot. Don’t store them in plastic and hanging them is better than boxes on the ground. The same storage rules apply to garlic.
  • It is the last call for sowing sweet corn. Given a reasonable summer and autumn it will mature just in time and then as temperatures drop, it will hold in the garden (it stops growing) part way into winter which greatly extends the fresh corn season. You may never buy frozen corn again.
  • With the many fruit trees sold in recent years, some readers will be picking their plums if they can beat the birds. The best time to prune and shape your plum tree is straight after harvest. You reduce the chance of silver blight entering the tree if you summer prune. The same applies to cherries, both ornamental and fruiting, almonds and indeed all stone and pip fruit and their ornamental relatives.