Garden pond myths: don’t plant bulrush

bulrush (Typha latifolia)

Much hated: bulrush (Typha latifolia)

Its a common piece of advice not to plant ‘invasive’ species like bulrush in a garden pond.

Here’s a typical quote from a source you would expect to trust:

‘Don’t plant reeds or reedmace (bulrushes) in a small garden pond – they are very invasive.’

There’s a couple of things wrong with this advice:

1. In a small pond, say the size of my garden pond, its easy to keep control of plants. Just hoik a bit out now and again if you don’t like them.

2. It ignores the habitat value of emergent plants, including bulrush. Bulrush is home to a variety of animals – like those shown below – and it provides habitat under the water.

Now that bulrush has come along in my pond on its own without needing to be added – I’m very pleased! And you can also try branched bur-reed, the various kinds of rushes (Juncus species), reed canary-grass and reed sweet-grass as well (if you’ve got room).

The story is different outside of gardens: bulrush is the one wetland plant that is spreading generally – its happy in our modern polluted and disturbed world, so I would try to stop it getting established in a new pond out in the countryside at first, just to give other plants a chance to get established.

Some bulrush beasts….

Bulrush bug (Chilacis typhae) - spends its life in the flower head of bulrushes

Bulrush bug (Chilacis typhae) - spends its life in the flower head of bulrushes (© Tristan Bantock)

Spotted backswimmer (Notonecta maculata) - a launch pad for flight (my garden pond)

Spotted backswimmer (Notonecta maculata) using young bulrush as a launch pad in my garden pond

Bulrush Wainscot moth (Nonagrea typhae) - larva burrows into the stems

Bulrush Wainscot moth (Nonagrea typhae) - the larvae burrow into bulrush stems (© Paul Harris)

Common reed beetle (Donacia aquatica): larvae eat the shoots of bulrush and pupate on the roots

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8 Responses to “Garden pond myths: don’t plant bulrush”

  1. Anthony Oates Says:

    Hello,
    another good thing about bull rushes is that female Aeshnea Cyanea dragonflies lay their eggs in the emerging stems of bull rushes. They have a sickle shaped ovipositor that the insert just above the water level….I’m waiting till next spring to watch them emerge and drop in to the water where they spend up to 4 years before metamorphosing in to adults when they will use the bull rushes to climb out and dry their wings before taking off and starting the process all over again.
    good luck with your ponds
    Ant.
    P.S. If you want photograph I can easily send you one.

  2. Debbie Says:

    We have recently converted an old swimming pool into a fish pond. All seemed to be going well until we planted bulrushes. It almost seems as if there is an oily surface to the pond now. Help anybody?

  3. Tristan Says:

    Jeremy, this is not a myth. I strongly advise you to get rid of the reedmace (I avoid the term ‘bulrush’ because it’s also used for Schoenoplectus lacustris) now, or you will regret it in a year or two. Your seedling probably looks pretty sweet and innocent now but believe you me but it has a habit of taking over.

    Reedmace is a good wildlife plant in the wild, but it’s just too large for most ponds – just like common reed, weeping willow etc. Even in the wild it quickly crowds out most other plants and will shade out that warm shallow water you have so carefully created. Even in bigger ponds and ornamental lakes it will need regular cutting. Like most pond plants, introducing it is easier than controlling or removing it. You have been warned!

    There are masses of good emergent plants you can grow that are much less thuggish – my favourite is Eleocharis palustris (spike-rush) which only grows to about 20cm and forms an open mat through which other emergents and submerged plants can grow. Or how about flowering rush Butomus umbellatus, or lesser marshwort Apium inundatum? Several of the sedges are also good – I grow bottle sedge Carex rostrata, which seems to go down well with the toad population. But even this needs annual control.

    Dragonflies are not generally fussy about what species they oviposit in and you certainly don’t need Typha to have breeding southern hawkers. I’ve had them ovipositing in soft mud by the side of my parents pond, and I think they will use a variety of plants such as flag irises and bog bean.

    Debbie – difficult to explain your oily surface without seeing the pond. But I have seen this around Typha and other tall emergents before and it’s generally quite common in sheltered ponds. I think it’s a bacterial film on the surface of the water, probably caused by an accumulation of organic matter in the pond combined with a lack of wave action. The bulrushes may contrbute to this by adding leafy material and by reducing turbulence and hence oxygen concentration. The bacteria themselves are generally harmless but you may see a reduction in the amount of oxygen dependent species such as mayfly nymphs.

    • jonspond Says:

      Well as with all this garden pond stuff if you fill it with high nutrient water I suspect that ‘bulrush’ along with other invasive species have a field day and multiply and ‘take over a pond’

      However Jeremy does give the advice that in a small pond you can hoik a bit out when it is taking over. The management of a pond should be a good clear out of the vegetation in the winter to mimic say grazing animals – removal of vegetation and the creation of bare areas is all about creating a good pond habitat.

      Its just goes against the ‘pond advice myths’ which are often given out. I have common reed in my pond which is approx 1m in diameter and around 20cm deep. I have to say that the spread of this plant has been very slow possibly due to the low nutrients in the water – so effectively these invasive plants become so when conditions allow them to be.

      • Tristan Says:

        Jon, it’s as important to plant the right plants as to control nutrients. By the time you realise there is a problem it can be very difficult to get on top of it again. Many larger marginals have tough rhizomes that are surprisingly difficult to remove without damaging your liner. Most garden ponds are much smaller than those in the wild and I think it’s good advice to scale down the size of the plants accordingly. I agree that creation of bare areas is a good idea, but this is a lot easier when removing water milfoil, water forget me not or clubrush than clearing a dense bed of sedges, reedmace or bur-reed.

        We all agree that controlling nutrients is really, really important. But nutrients in water tend to be a lot more mobile and available than in soil, so maintaining low nutrient levels in a pond can be difficult for many gardeners. Growing smaller and less invasive plants is an insurance policy against nutrients finding their way into the pond.

        All of this doesn’t mean it’s impossible to grow large marginals in a small pond without any problems. It’s just harder to do. That’s why I think the advice to grow smaller plants is good advice. Also, many of the smaller species are, frankly, more ornamental and more threatened in the wider countryside.

  4. Andre McLean Says:

    Reed mace have taken over the pond in my field (about 7 meters by 15 meters), it used to have newts and dragonflies and plenty of wildlife, all sadly reduced with loss of open water. Any suggestions about how to reduce it to about half.

    • Jeremy Biggs Says:

      Hi Andre – SImplest way is to pull it out manually or mechanically. For detailed info get The Pond Book – which we publish or free to members when you join Pond Conservation. Jeremy

    • jonspond Says:

      Is there any room to create a new pond? a new pond would be ideal way forward. Plants growing in ponds often reduce the detectability of the animals we are looking for so even though the animals are still there we do not see them thus leading us to the conclusion they have declined.

      Digging out ponds can be beneficial but it can also cause damage to communities of plants and animals which live in weedy or vegetated ponds. I would recommend the Pond Book as the main text to refer to when looking at these sort of issues!

      Regards

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