Giant Reed Mace

paddy-s · Hazel Tree Joined: 01 Aug 2008 Posts: 24 Location: Sligo

Hi.

We have a large pond and are doubling the size of it. Giant reed mace is trying to take over the old part and is putting roots into the new section. I have tried cutting it down to root level [under water] but new shoots keep coming up. Would rubbing Roundup on the leaves kill it off without affecting the other plants and wildlife.

GPI · Posted: Mon Aug 11, 2008 3:09 pm Post subject:

Even though it is hard work, hand pulling would be better than cutting in my opinion, if repeated annually for several years.
If hand pulling, wear a pair of strong gloves.
The best time to carry this out hand pulling is at end of July into early August to weaken the plant, as most of the food reserves produced that season are lost.

If hand pulling is too difficult, a petrol hedge trimmers or strimmers with strong cord/circular blade can be used to cut down the reeds much quicker.
Be aware that these tools are dangerous to work with, especially on the bank of a pond.
No matter wheather you pull the reeds or cut them, you must remove all floating reed debris as you go.

A follow on method which is very effective in reed reduction is after cutting/pulling reeds, place a sheet of black plastic over the cut area, weighed down by using sand bags/rocks and rope.
If the area recives good sunlight, the high temperatures beneath the plastic will help kill off the re-emerging plants.
The plastic can then be removed the following spring. If a few reeds return, these can easily be pulled.

You can of course paint on Roundup onto the cut stems (cut them higher than the waterline in this case), and leave any lower leaves intact for painting as well. There is a good chance that it may have some effect on the other plants and wildlife in the pond especially if rain fall comes close after the application. So time it well.

If it was my pond I would avoid using the roundup because
Glyphosate which is in roundup is slightly toxic to fish, mammals birds etc.
Also under Irish and EU law it is illegal to use any preparation as a pesticide/fugicide/herbicide that is not approved for such use.
And as far as I know roundup is not approved as an aquatic herbicide.
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